Application Setup

Introduction

A text-based database is an application used to create, keep, and manage records. You have many options. One way to store the records of a database is as text. Even then, you still have many option. One solution is to create and manage records using a collection class.

Besides using a collection class to create and manage records, you also have to decide in what format you would keep the record. For this example, we will save the records in XML.

Practical Learning: Introducing MDI Applications

1. Start Microsoft Visual Studio
2. In the Visual Studio 2022 dialog box, click Create a New Project
3. In the Create a New Project dialog box, in the Languages combo box, select C#
4. In the list of projects templates, click Windows Forms App
5. Click Next
6. Change the Project Name to StellarWaterPoint5
7. In the Framework combo box, select the highest version: .NET 9.0 (Standard Term Suppot)
8. Click Create
9. In the Solution Explorer, right-click StellarWaterPoint5 -> Add -> New Folder
10. Type Models as the name of the folder
11. In the Solution Explorer, right-click Form1.cs and click Rename
12. Change the name to WaterDistribution.cs
13. Press Enter twice to accept the name and dismiss the message box
14. Double-click an unoccupied of the form to generate its Load event
15. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
        }
    }

16. Return to the form and click its body to select it
17. In the Properties window, change the following characteristics:
    IsMdiContainer: True
    StartPosition: CenterScreen
    Text: Stellar Water Point

    

18. To create a form, on the main menu, click Project -> Add Form (Windows Forms)...
19. In the middle list, click About Box (Windows Forms)
20. Change the file Name to AboutSWP
21. In the Toolbox, expand Menus & Toolbars
22. In the Menus & Toolbars section of the Toolbox, click MenuStrip and click the form
23. In the Properties window, click (Name) and type msMainMenu
24. Still in the Properties window, click Items and click its button
25. Using the Add button, create some menu items as follows:

    Text	(Name)
    &File	miFile
    Water &Bills	miWaterBills
    &Customers	miCustomers
    Water &Meters	miWaterMeters
    &Window	miWindow
    &Help	miHelp

26. In the Members list of the Items Collection Editor, click miFile
27. In the right list, click DropDownItems and click its button
28. Using the Add button, create an item as follows:

    Text	(Name)	Shortcuts
    E&xit	miFileExit	Alt + F4

29. On the Items Collection Editor (miFile.DropDownItems) dialog box, click OK
30. In the Members list of the Items Collection Editor, click miWaterBills
31. In the right list, click DropDownItems and click its button
32. Using the Add button, create two items as follows:

    Text	(Name)	Shortcuts
    &Process Water Bill...	miWaterBillsCreate	Ctrl+Shift+B
    Water Bill &Details...	miWaterBillsDetails	Ctrl+Shift+D
    Water Bill &Editor...	miWaterBillsEditor	Ctrl+Shift+E
    &Delete Water Bill...	miWaterBillsDeletion	Ctrl+Shift+D
    	tsWaterBillsSeparator
    &View Water Bills...	miWaterBillsView	Ctrl+Shift+V

33. On the Items Collection Editor (miWaterBills.DropDownItems) dialog box, click OK
34. In the Members list of the Items Collection Editor, click miCustomers
35. In the right list, click DropDownItems and click its button
36. Using the Add button, create two items as follows:

    Text	(Name)	Shortcuts
    &Create Customer Account...	miCustomersCreate	Ctrl+Shift+C
    Customer Account &Details...	miCustomersDetails	Ctrl+Shift+U
    Customer Account &Editor...	miCustomersEditor	Ctrl+Shift+T
    &Delete Customer Account...	miCustomersDelete	Ctrl+Shift+O
    	tsCustomersSeparator
    &View Customers Accounts...	miViewCustomers	Ctrl+Shift+R

37. On the Items Collection Editor (miCustomers.DropDownItems) dialog box, click OK
38. In the Members list of the Items Collection Editor, click miWaterMeters
39. In the right list, click DropDownItems and click its button
40. Using the Add button, create two items as follows:

    Text	(Name)	Shortcuts
    &Setup Water Meter...	miWaterMetersCreate	Ctrl+Shift+W
    Water Meter &Details...	miWaterMetersDetails	Ctrl+Shift+I
    &Update Water Meter...	miWaterMetersEditor	Ctrl+Shift+A
    De&lete Water Meter...	miWaterMetersDelete	Ctrl+Shift+R
    	tsWaterMetersSeparator
    View Wate&r Meters...	miViewWaterMeters	Ctrl+Shift+E

41. On the Items Collection Editor (miWaterMeters.DropDownItems) dialog box, click OK
42. In the Members list of the Items Collection Editor, click miWindow
43. In the right list, click DropDownItems and click its button
44. Using the Add button, create two items as follows:

    Text	(Name)
    &Arrange	miWindowArrange
    &Cascade	miWindowCascade
    Tile &Horizontal	miWindowTileHorizontal
    Tile &Vertical	miWindowTileVertical

45. On the Items Collection Editor (miWindow.DropDownItems) dialog box, click OK
46. In the Members list of the Items Collection Editor, click miHelp
47. In the right list, click DropDownItems and click its button
48. Using the Add button, create an item as follows:

    Text	(Name)	Shortcuts
    &About Stellar Water Point...	miHelpAbout	Ctrl+F1

49. On the Items Collection Editor (miHelp.DropDownItems) dialog box, click OK
50. On the Items Collection Editor dialog box, click OK
51. On the form, click the Window menu item and double-click Arrange
52. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
        }
    }

53. Return to the Stellar Water Point form and, below Arrange, double-click Cascade
54. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
        }
    }

55. Return to the Stellar Water Point form and, below Cascade, double-click Tile Horizontal
56. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
        }
    }

57. Return to the Stellar Water Point form and, below Tile Horizontal, double-click Tile Vertical
58. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
        }
    }

59. Return to the Stellar Water Point form

Water Meters

Introduction

.

Practical Learning: Starting Water Meters Issues

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. On the main menu, click Project -> Add Class...
3. Replace the name with WaterMeter
4. Click Add
5. Change the code as follows:

   namespace StellarWaterPoint5.Models
   {
       public record WaterMeter
       {
           public string? MeterNumber { get; set; }
           public string? Make        { get; set; }
           public string? Model       { get; set; }
           public string? MeterSize   { get; set; }
       }
   }

6. In the Solution Explorer, right-click StellarWaterPoint1 -> Add -> New Folder
7. Type WaterMeters as the name of the folder

Displaying Water Meters

To let the user see a list of the water meters in the database, we will use a form equipped with a list view.

Practical Learning: Displaying Water Meters

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	Width	TextAlign
   colWaterMeterId	Id	40
   colMeterNumber	Meter #	150	Center
   colMake	Make	300
   colModel	Model	150
   colMeterSize	Meter Size	150

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwWaterMeters	FullRowSelect: True GridLines: True View: Details

9. Click an unoccupied area of the form to select it
10. In the Solution Explorer, click the Events button
11. In the Events section of the Properties window, double-click Activated
12. Change the document as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint5.Models;
    
    namespace StellarWaterPoint5.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = @"E:\Stellar Water Point\WaterMeters.xml";
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        int counter = 1;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter wm in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(counter++.ToString());
    
                            lviWaterMeter.SubItems.Add(wm.MeterNumber);
                            lviWaterMeter.SubItems.Add(wm.Make);
                            lviWaterMeter.SubItems.Add(wm.Model);
                            lviWaterMeter.SubItems.Add(wm.MeterSize);
    
                            lvwWaterMeters.Items.Add(lviWaterMeter);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
        }
    }

13. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
14. Change the document as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public  static bool WaterMetersDisplaying;
            private WaterMeters.Central waterMeters;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
        }
    }

15. In the Solution Explorer, in the WaterMeters folder, double-click Central (make sure the form is selected)
16. In the Events section of the Properties window, double-click FormClosing
17. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint5.Models;
    
    namespace StellarWaterPoint5.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = @"E:\Stellar Water Point\WaterMeters.xml";
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        int counter = 1;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter wm in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(counter++.ToString());
    
                            lviWaterMeter.SubItems.Add(wm.MeterNumber);
                            lviWaterMeter.SubItems.Add(wm.Make);
                            lviWaterMeter.SubItems.Add(wm.Model);
                            lviWaterMeter.SubItems.Add(wm.MeterSize);
    
                            lvwWaterMeters.Items.Add(lviWaterMeter);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void Central_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterMetersDisplaying == true)
                {
                    WaterDistribution.WaterMetersDisplaying = false;
                    Close();
                }
            }
        }
    }

18. In the Solution Explorer, double-click WaterDistribution.cs to display the form
19. On the menu that was designed on the form, click Water Meters and, below it, double-click View Water Meters...
20. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            private WaterMeters.Central waterMeters;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
    
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersViews_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
        }
    }

A Water Meter Record

.

Practical Learning: Creating a Water Meter Record

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form(Windows Forms)...
2. Type Create
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-00-000
   Label			M&ake:
   TextBox		txtMake
   Label			M&odel:
   TextBox		txtModel
   Label			Me&ter Size:
   TextBox		txtMeterSize
   Button		btnSaveWateMeter	S&ave Water Meter	DialogResult: OK
   Button		btnClose	&Close

5. Click an unoccupied area of the form to select it and, in the Properties window, change the following characteristics:

   Text:         Stellar Water Point - Water Meter Setup
   AcceptButton: btnSaveWateMeter

6. On the form, double-click the S&ave Water Meter button
7. Return to the form and double-click the &Close button
8. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint5.Models;
   
   namespace StellarWaterPoint5.WaterMeters
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnSaveWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a meter number. " +
                                   "Otherwise, the water meter cannot be set up.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter> ();
               string strWaterMeters        = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters  = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters       = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists     == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
                   }
               }
   
               WaterMeter wm   = new WaterMeter()
               {
                   MeterNumber = mtbMeterNumber.Text,
                   Make        = txtMake.Text,
                   Model       = txtModel.Text,
                   MeterSize   = txtMeterSize.Text
               };
               waterMeters.Add(wm);
   
               using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
               {
                   xsWaterMeters.Serialize(twWaterMeters, waterMeters);
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

9. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
10. Change the document as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying      = false;
                WaterMeterCreateDisplaying = false;
    
                waterMeters                = new WaterMeters.Central();
                waterMeterCreate           = new WaterMeters.Create();
    
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersViews_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
        }
    }

11. In the Solution Explorer, in the WaterMeters folder, double-click Create
12. Click an unoccupied area of the form to select it
13. In the Solution Explorer, click the Events button
14. In the Events section of the Properties window, double-click FormClosing
15. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint5.Models;
    
    namespace StellarWaterPoint5.WaterMeters
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnSaveWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a meter number. " +
                                    "Otherwise, the water meter cannot be set up.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
                    }
                }
    
                WaterMeter wm = new WaterMeter()
                {
                    MeterNumber = mtbMeterNumber.Text,
                    Make = txtMake.Text,
                    Model = txtModel.Text,
                    MeterSize = txtMeterSize.Text
                };
                waterMeters.Add(wm);
    
                using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
                {
                    xsWaterMeters.Serialize(twWaterMeters, waterMeters);
                }
    
                Close();
            }
    
            private void Create_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterMeterCreateDisplaying == true)
                {
                    WaterDistribution.WaterMeterCreateDisplaying = false;
                    Close();
                }
            }
        }
    }

16. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
17. On the menu that was designed on the form, click Water Meters and, below it, double-click Setup Water Meter...
18. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWaterMetersViews_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if(WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
        }
    }

19. To execute, on the main menu, click Debug -> Start Without Debugging:

    

20. On the main menu, click Water Meters and click View Water Meters...:

    

21. On the main menu, click Water Meters and click Setup Water Meter...:

    

22. Enter the value for each of the following records and click OK (or press Enter) for each:

    Meter #	Make	Model	Meter Size
    392-494-572	Constance Technologies	TG-4822	5/8 Inches
    938-705-869	Stan Wood	66-G	1 Inch
    588-279-663	Estellano	NCF-226	3/4 Inches

    

23. Close the forms and return to your programming environment

Water Meter Details

.

Practical Learning: Creating a Water Meter Record

1. To create a form, in the Solution Explorer, right-click the WaterMeters folder -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Modifiers	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Public	Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Make:
   TextBox		txtMake		False	Public
   Label			Model:
   TextBox		txtModel		False	Public
   Label			Meter Size:
   TextBox		txtMeterSize		False	Public
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint5.Models;
   
   namespace StellarWaterPoint5.WaterMeters
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters        = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters  = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters       = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists     == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter       = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
9. Change the document as follows:

   namespace StellarWaterPoint5
   {
       public partial class WaterDistribution : Form
       {
           public static bool WaterMetersDisplaying;
           public static bool WaterMeterCreateDisplaying;
           public static bool WaterMeterDetailsDisplaying;
   
           private WaterMeters.Central waterMeters;
           private WaterMeters.Create  waterMeterCreate;
           private WaterMeters.Details  waterMeterDetails;
   
           public WaterDistribution()
           {
               InitializeComponent();
   
               WaterMetersDisplaying      = false;
               WaterMeterCreateDisplaying = false;
               WaterMeterDetailsDisplaying = false;
   
               waterMeters                = new WaterMeters.Central();
               waterMeterCreate           = new WaterMeters.Create();
               waterMeterDetails           = new WaterMeters.Details();
   
               Directory.CreateDirectory(@"C:\Stellar Water Point8");
           }
   
           private void WaterDistribution_Load(object sender, EventArgs e)
           {
               Directory.CreateDirectory(@"C:\Stellar Water Point8");
           }
   
           private void miWindowArrange_Click(object sender, EventArgs e)
           {
               LayoutMdi(MdiLayout.ArrangeIcons);
           }
   
           private void miWindowCascade_Click(object sender, EventArgs e)
           {
               LayoutMdi(MdiLayout.Cascade);
           }
   
           private void miWindowTileHorizontal_Click(object sender, EventArgs e)
           {
               LayoutMdi(MdiLayout.TileHorizontal);
           }
   
           private void miWindowTileVertical_Click(object sender, EventArgs e)
           {
               LayoutMdi(MdiLayout.TileVertical);
           }
   
           private void miWaterMetersViews_Click(object sender, EventArgs e)
           {
               if (WaterMetersDisplaying == false)
               {
                   waterMeters = new WaterMeters.Central();
   
                   waterMeters.MdiParent = this;
                   waterMeters.Show();
   
                   WaterMetersDisplaying = true;
               }
               else
               {
                   waterMeters.BringToFront();
               }
           }
   
           private void miWaterMetersCreate_Click(object sender, EventArgs e)
           {
               if (WaterMeterCreateDisplaying == false)
               {
                   waterMeterCreate = new();
                   waterMeterCreate.MdiParent = this;
                   waterMeterCreate.Show();
   
                   WaterMeterCreateDisplaying = true;
               }
               else
               {
                   waterMeterCreate.BringToFront();
               }
           }
       }
   }

10. In the Solution Explorer, in the WaterMeters folder, double-click Details
11. Click an unoccupied area of the form to select it
12. In the Solution Explorer, click the Events button
13. In the Events section of the Properties window, double-click FormClosing
14. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint5.Models;
    
    namespace StellarWaterPoint5.WaterMeters
    {
        public partial class Details : Form
        {
            public Details()
            {
                InitializeComponent();
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMake.Text = meter.Make;
                            txtModel.Text = meter.Model;
                            txtMeterSize.Text = meter.MeterSize;
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Details_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterMeterDetailsDisplaying == true)
                {
                    WaterDistribution.WaterMeterDetailsDisplaying = false;
                    Close();
                }
            }
        }
    }

15. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
16. On the menu bar of the form, click Water Meters and, below it, double-click Water Meter Details...
17. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersViews_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
        }
    }

18. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

19. On the main menu of the Stellar Water Point form, click View Water Meters:

    

20. Again, on the main menu of the form, click Water Meters and click Water Meter Details:

    

21. In the Meter # text, type 392-494-572
22. Click the Find Water Button button:

    

23. Close the forms and return to your programming environment

Updating a Water Meter Record

.

Practical Learning: Updating a Water Meter

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Editor as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Make:
   TextBox		txtMake		False
   Label			Model:
   TextBox		txtModel		False
   Label			Meter Size:
   TextBox		txtMeterSize		False
   Button		btnUpdateWateMeter	&Update Wate Meter
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Change the document as follows:

   using StellarWaterPoint5.Models;
   using System.Xml.Serialization;
   
   namespace StellarWaterPoint5.WaterMeters
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
       }
   }

7. Return to the form and double-click the Update Water Meter button
8. Implement the event as follows:

   using StellarWaterPoint5.Models;
   using System.Xml.Serialization;
   
   namespace StellarWaterPoint5.WaterMeters
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
   
           private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       waterMeters.ForEach(meter =>
                       {
                           if (meter.MeterNumber == mtbMeterNumber.Text)
                           {
                               meter.Make      = txtMake.Text;
                               meter.Model     = txtModel.Text;
                               meter.MeterSize = txtMeterSize.Text;
                           }
                       });
                   }
               }
   
               using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
               {
                   xsWaterMeters.Serialize(twWaterMeters, waterMeters);
               }
   
               Close();
           }
       }
   }

9. Return to the form and double-click the Close button
10. Implement the event as follows:

    using StellarWaterPoint5.Models;
    using System.Xml.Serialization;
    
    namespace StellarWaterPoint5.WaterMeters
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMake.Text = meter.Make;
                            txtModel.Text = meter.Model;
                            txtMeterSize.Text = meter.MeterSize;
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        waterMeters.ForEach(meter =>
                        {
                            if (meter.MeterNumber == mtbMeterNumber.Text)
                            {
                                meter.Make      = txtMake.Text;
                                meter.Model     = txtModel.Text;
                                meter.MeterSize = txtMeterSize.Text;
                            }
                        });
                    }
                }
    
                using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
                {
                    xsWaterMeters.Serialize(twWaterMeters, waterMeters);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

11. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
12. Change the document as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool           WaterMetersDisplaying;
            public static bool           WaterMeterCreateDisplaying;
            public static bool           WaterMeterDetailsDisplaying;
            public static bool           WaterMeterEditorDisplaying;
    
            private WaterMeters.Central  waterMeters;
            private WaterMeters.Create   waterMeterCreate;
            private WaterMeters.Details  waterMeterDetails;
            private WaterMeters.Editor   waterMeterEditor;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
    
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersViews_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
        }
    }

13. In the Solution Explorer, in the WaterMeters folder, double-click Editor
14. Click an unoccupied area of the form to select it
15. In the Solution Explorer, click the Events button
16. In the Events section of the Properties window, double-click FormClosing
17. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterMeters
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMake.Text = meter.Make;
                            txtModel.Text = meter.Model;
                            txtMeterSize.Text = meter.MeterSize;
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        waterMeters.ForEach(meter =>
                        {
                            if (meter.MeterNumber == mtbMeterNumber.Text)
                            {
                                txtMake.Text = meter.Make;
                                txtModel.Text = meter.Model;
                                txtMeterSize.Text = meter.MeterSize;
                            }
                        });
                    }
                }
    
                using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
                {
                    xsWaterMeters.Serialize(twWaterMeters, waterMeters);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Editor_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterMeterEditorDisplaying == true)
                {
                    WaterDistribution.WaterMeterEditorDisplaying = false;
                    Close();
                }
            }
        }
    }

18. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
19. On the menu bar of the form, click Water Meters and, below it, double-click Update Water Meter...
20. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool              WaterMetersDisplaying;
            public static bool              WaterMeterCreateDisplaying;
            public static bool              WaterMeterDetailsDisplaying;
            public static bool              WaterMeterEditorDisplaying;
    
            private WaterMeters.Central     waterMeters;
            private WaterMeters.Create      waterMeterCreate;
            private WaterMeters.Details     waterMeterDetails;
            private WaterMeters.Editor      waterMeterEditor;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
        }
    }

21. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

22. On the main menu of the central form of the application, click Water Meters and click View Water Meters

    

23. On the main menu of the central form of the application, click Water Meters and click Update Water Meter

    

24. Click the Edit Water Meter button
25. In the Meter # text, type 938-705-869
26. Click the Find Water Meter button

    

27. Change the values as follows:

    Make:	Stanford Trend
    Model:	266G
    Meter Size:	1 1/2 Inches

    

28. Click the Update Water Meter button:

    

29. Close the forms and return to your programming environment

Deleting a Water Meter Record

.

Practical Learning: Deleting a Water Meter Record

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form(Windows Forms)...
2. In the Name text box, replace the string with Delete as the name of the form
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Make:
   TextBox		txtMake		False
   Label			Model:
   TextBox		txtModel		False
   Label			Meter Size:
   TextBox		txtMeterSize		False
   Button		btnDeleteWaterMeter	&Delete Water Meter
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Change the document as follows:

   using StellarWaterPoint5.Models;
   using System.Xml.Serialization;
   
   namespace StellarWaterPoint5.WaterMeters
   {
       public partial class Delete : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if(string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
       }
   }

7. Return to the form and double-click the Delete Water Meter button
8. Return to the form and double-click the Close button
9. Implement the events as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterMeters
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
   
           private void btnDeleteWaterMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
                       
                       foreach(WaterMeter meter in waterMeters)
                       {
                           if (meter.MeterNumber == mtbMeterNumber.Text)
                           {
                               if(MessageBox.Show("Are you sure you want to delete the water meter with meter number " +
                                                   mtbMeterNumber.Text + "?",
                                                   "Stellar Water Point",
                                                   MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
                               {
                                   waterMeters.Remove(meter);
   
                                   MessageBox.Show("The water meter whose meter number is " +
                                                   mtbMeterNumber.Text + " is going to be removed from our system.",
                                                   "Stellar Water Point",
                                                   MessageBoxButtons.OK, MessageBoxIcon.Information);
                                   break;
                               }
                           }
                       }
                   }
               }
   
               using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
               {
                   xsWaterMeters.Serialize(twWaterMeters, waterMeters);
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
11. Change the document as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool           WaterMetersDisplaying;
            public static bool           WaterMeterCreateDisplaying;
            public static bool           WaterMeterDetailsDisplaying;
            public static bool           WaterMeterEditorDisplaying;
            public static bool           WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central  waterMeters;
            private WaterMeters.Create   waterMeterCreate;
            private WaterMeters.Details  waterMeterDetails;
            private WaterMeters.Editor   waterMeterEditor;
            private WaterMeters.Delete   waterMeterDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

12. In the Solution Explorer, in the WaterMeters folder, double-click Delete
13. Click an unoccupied area of the form to select it
14. In the Solution Explorer, click the Events button
15. In the Events section of the Properties window, double-click FormClosing
16. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterMeters
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMake.Text = meter.Make;
                            txtModel.Text = meter.Model;
                            txtMeterSize.Text = meter.MeterSize;
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnDeleteWaterMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        waterMeters.ForEach(meter =>
                        {
                            if (meter.MeterNumber == mtbMeterNumber.Text)
                            {
                                waterMeters.Remove(meter);
                            }
                        });
                    }
                }
    
                using (TextWriter twWaterMeters = new StreamWriter(fiWaterMeters.FullName))
                {
                    xsWaterMeters.Serialize(twWaterMeters, waterMeters);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Delete_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterMeterDeleteDisplaying == true)
                {
                    WaterDistribution.WaterMeterDeleteDisplaying = false;
                    Close();
                }
            }
        }
    }

17. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
18. On the menu bar of the form, click Water Meters and, below it, double-click Delete Water Meter...
19. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
        }
    }

20. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

21. On the main menu of the central form of the application, click Water Meters and click View Water Meters

    

22. On the main menu of the central form of the application, click Water Meters and click Delete Water Meter

    

23. In the Meter # text, type 938-705-869
24. Click the Find Water Meter button

    

25. Click the Delete Water Meter button. Tead the first message box and click Yes. Then click OK on the second message box:

    

26. In the same way, delete one of the other two records to leave the other record in the document
27. Close the forms and return to your programming environment
28. From the Windows Explorer, open the WaterMeters.xml file
29. Replace the content of the file with the provided file
30. Save the file
31. Return to your programming environment

Customers

Introduction

.

Practical Learning: Starting Water Meters Issues

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. On the main menu, click Project -> Add Class...
3. Replace the name with Customer
4. Click Add
5. Change the code as follows:

   namespace StellarWaterPoint5.Models
   {
       public record Customer
       {
           public string? AccountNumber { get; set; }
           public string? AccountName   { get; set; }
           public string? AccountType   { get; set; }
           public string? MeterNumber   { get; set; }
           public string? Address       { get; set; }
           public string? City          { get; set; }
           public string? County        { get; set; }
           public string? State         { get; set; }
           public string? ZIPCode       { get; set; }
       }
   }

6. In the Solution Explorer, right-click StellarWaterPoint1 -> Add -> New Folder
7. Type Customers as the name of the folder

Displaying Customers Records

.

Practical Learning: Displaying Water Meters

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	TextAlign	Width
   colCustomerId	Id		40
   colAccountNumber	Account #	Center	150
   colAccountName	Account Name		200
   colAccountType	Account Type		200
   colMeterNumber	Meter #	Center	100
   colAddress	Address		250
   colCity	City		125
   colCounty	County		125
   colState	State	Center
   colZIPCode	ZIP-Code	Center	125

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details

9. Click an unoccupied area of the form to select it
10. In the Solution Explorer, click the Events button
11. In the Events section of the Properties window, double-click Activated
12. Change the document as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                List<Customer> clients = new List<Customer>();
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        int counter = 1;
    
                        lvwCustomers.Items.Clear();
    
                        foreach (Customer client in clients)
                        {
                            ListViewItem lviCustomer = new ListViewItem(counter++.ToString());
    
                            lviCustomer.SubItems.Add(client.AccountNumber);
                            lviCustomer.SubItems.Add(client.AccountName);
                            lviCustomer.SubItems.Add(client.AccountType);
                            lviCustomer.SubItems.Add(client.MeterNumber);
                            lviCustomer.SubItems.Add(client.Address);
                            lviCustomer.SubItems.Add(client.City);
                            lviCustomer.SubItems.Add(client.County);
                            lviCustomer.SubItems.Add(client.State);
                            lviCustomer.SubItems.Add(client.ZIPCode);
    
                            lvwCustomers.Items.Add(lviCustomer);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowCustomers();
            }
        }
    }

13. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
14. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
            private Customers.Central customers;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
    
                customers = new Customers.Central();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

15. In the Solution Explorer, in the Customers folder, double-click Central (make sure the form is selected)
16. In the Events section of the Properties window, double-click FormClosing
17. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                List<Customer> clients = new List<Customer>();
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        int counter = 1;
    
                        lvwCustomers.Items.Clear();
    
                        foreach (Customer client in clients)
                        {
                            ListViewItem lviCustomer = new ListViewItem(counter++.ToString());
    
                            lviCustomer.SubItems.Add(client.AccountNumber);
                            lviCustomer.SubItems.Add(client.AccountName);
                            lviCustomer.SubItems.Add(client.AccountType);
                            lviCustomer.SubItems.Add(client.MeterNumber);
                            lviCustomer.SubItems.Add(client.Address);
                            lviCustomer.SubItems.Add(client.City);
                            lviCustomer.SubItems.Add(client.County);
                            lviCustomer.SubItems.Add(client.State);
                            lviCustomer.SubItems.Add(client.ZIPCode);
    
                            lvwCustomers.Items.Add(lviCustomer);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void Central_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.CustomersDisplaying == true)
                {
                    WaterDistribution.CustomersDisplaying = false;
                    Close();
                }
            }
        }
    }

18. In the Solution Explorer, double-click WaterDistribution.cs to display the form
19. On the menu that was designed on the form, click Customers and, below it, double-click View Customers Accounts...
20. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
    
            private Customers.Central customers;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
    
                customers = new Customers.Central();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
        }
    }

A Customer Record

.

Practical Learning: Creating a Customer Record

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form(Windows Forms)...
2. Type Create
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Label			&Account Name:
   TextBox		txtAccountName
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   ComboBox		cbxAccountsTypes		Items: OTH - Other BUS - General Business RES - Residential Household SGO - Social/Government/Non-Profit Organization UUO - Unidentified or Unclassified Type of Organization WAT - Water Intensive Business (Laudromat, Hair Salon, Restaurant, etc
   Label			&Address:
   TextBox		txtAddress
   Label			C&ity:
   TextBox		txtCity
   Label			C&ounty:
   TextBox		txtCounty
   Label			&State:
   TextBox		txtState
   Label			&ZIP-Code:
   MaskedTextBox		mtbZIPCode		Masked: Zip-Code
   Button		btnSaveCustomerAccount	S&ave Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. On the form, double-click the Find Water Meter button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
       }
   }

7. Return to the form and double-click the S&ave Customer Account button
8. Return to the form and double-click the &Close button
9. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
   
           private void btnSaveCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must provide an account number of the customer whose account you are creating. " +
                                   "Otherwise, the new customer account cannot be created.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
                   }
               }
   
               Customer client = new()
               {
                   AccountNumber = mtbAccountNumber.Text,
                   AccountName   = txtAccountName.Text,
                   AccountType   = cbxAccountsTypes.Text,
                   MeterNumber   = mtbMeterNumber.Text,
                   Address       = txtAddress.Text,
                   City          = txtCity.Text,
                   County        = txtCounty.Text,
                   State         = txtState.Text,
                   ZIPCode       = mtbZIPCode.Text
               };
               
               clients.Add(client);
   
               using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
               {
                   xsCustomers.Serialize(twCustomers, clients);
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
11. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
    
                customers                   = new Customers.Central();
                clientCreate                = new Customers.Create();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
        }
    }

12. In the Solution Explorer, in the Customers folder, double-click Create
13. Click an unoccupied area of the form to select it
14. In the Solution Explorer, click the Events button
15. In the Events section of the Properties window, double-click FormClosing
16. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnSaveCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must provide an account number of the customer whose account you are creating. " +
                                    "Otherwise, the new customer account cannot be created.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
                    }
                }
    
                Customer client = new()
                {
                    AccountNumber = mtbAccountNumber.Text,
                    AccountName   = txtAccountName.Text,
                    AccountType   = cbxAccountsTypes.Text,
                    MeterNumber   = mtbMeterNumber.Text,
                    Address       = txtAddress.Text,
                    City          = txtCity.Text,
                    County        = txtCounty.Text,
                    State         = txtState.Text,
                    ZIPCode       = mtbZIPCode.Text
                };
                
                clients.Add(client);
    
                using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
                {
                    xsCustomers.Serialize(twCustomers, clients);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Create_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.CustomerCreateDisplaying == true)
                {
                    WaterDistribution.CustomerCreateDisplaying = false;
                    Close();
                }
            }
        }
    }

17. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
18. On the menu that was designed on the form, click Customers and, below it, double-click Setup Water Meter...
19. Implement the event as follows:

    namespace StellarWaterPoint5
    {
        public partial class WaterDistribution : Form
        {
            public static bool CustomersDisplaying;
            public static bool CustomerCreateDisplaying;
    
            private Customers.Central waterMeters;
            private Customers.Create waterMeterCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
    
                waterMeters = new Customers.Central();
                waterMeterCreate = new Customers.Create();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miCustomersViews_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    waterMeters = new Customers.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miCustomersCreate_Click(object sender, EventArgs e)
            {
                if(CustomerCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    CustomerCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
        }
    }

20. To execute, on the main menu, click Debug -> Start Without Debugging:

    

21. On the main menu, click Customers and click View Customers Accounts...:

    

22. On the main menu, click Customers and click Create Customer Account...:

    

23. In the account # text box, type 9279-570-8394
24. In the meter # text box, type 799-528-461
25. Click the Find water meter button
26. Enter the other values as follows:

    Account #:    9279-570-8394
    Account Name: Thomas Stones
    Meter #:      799-528-461
    Account Type: RES - Residential Household
    Address:      10252 Broward Ave #D4
    City:         Frederick
    County:       Frederick
    State:        MD
    ZIP-Code:     21703-4422

27. Click Save Customer Account
28. In the same way, create the following two records:

    Account #	Account Name	Meter #	Account Type	Address	City	County	State	ZIP-Code
    4086-938-4783	Hernola Dough	594-827-359	UUO - Unidentified or Unclassified Type of Organization	10 10 Hexagonal Drv	Winston	Yoke	Penn	11402-4411
    7080-583-5947	Sunny Yard	827-508-248	WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc	663 Sherry Wood East Street	Shimpstown	Franklin	PA	17236-2626

    

29. Close the forms and return to your programming environment

The Details of a Customer Account

.

Practical Learning: Viewing the Details of a Customer Account

1. To create a form, in the Solution Explorer, right-click the Customers folder -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Button		btnFindCustomerAccount	&Find Customer Account
   Label			&Account Name:
   TextBox		txtAccountName		Enabled: False
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   TextBox		txtAccountsTypes		Enabled: False
   Label			&Address:
   TextBox		txtAddress		Enabled: False
   Label			C&ity:
   TextBox		txtCity		Enabled: False
   Label			C&ounty:
   TextBox		txtCounty		Enabled: False
   Label			&State:
   TextBox		txtState		Enabled: False
   Label			&ZIP-Code:
   TextBox		txtZIPCode		Enabled: False
   Button		btnClose	&Close

5. On the form, double-click the Find Customer Account button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using StellarWaterPoint50.Models;
   using System.Xml.Serialization;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to view.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
9. Change the document as follows:

   namespace StellarWaterPoint50
   {
       public partial class WaterDistribution : Form
       {
           public static bool          WaterMetersDisplaying;
           public static bool          WaterMeterCreateDisplaying;
           public static bool          WaterMeterDetailsDisplaying;
           public static bool          WaterMeterEditorDisplaying;
           public static bool          WaterMeterDeleteDisplaying;
   
           private WaterMeters.Central waterMeters;
           private WaterMeters.Create  waterMeterCreate;
           private WaterMeters.Details waterMeterDetails;
           private WaterMeters.Editor  waterMeterEditor;
           private WaterMeters.Delete  waterMeterDelete;
   
           public static bool          CustomersDisplaying;
           public static bool          CustomerCreateDisplaying;
           public static bool          CustomerDetailsDisplaying;
   
           private Customers.Central   customers;
           private Customers.Create    customerCreate;
           private Customers.Details   customerDetails;
   
           public WaterDistribution()
           {
               InitializeComponent();
   
               WaterMetersDisplaying       = false;
               WaterMeterCreateDisplaying  = false;
               WaterMeterDetailsDisplaying = false;
               WaterMeterEditorDisplaying  = false;
               WaterMeterDeleteDisplaying  = false;
   
               waterMeters                 = new WaterMeters.Central();
               waterMeterCreate            = new WaterMeters.Create();
               waterMeterDetails           = new WaterMeters.Details();
               waterMeterEditor            = new WaterMeters.Editor();
               waterMeterDelete            = new WaterMeters.Delete();
   
               CustomersDisplaying         = false;
               CustomerCreateDisplaying    = false;
               CustomerDetailsDisplaying   = false;
   
               customers                   = new Customers.Central();
               customerCreate              = new Customers.Create();
               customerDetails             = new Customers.Details();
           }
   
           private void WaterDistribution_Load(object sender, EventArgs e)
           {
               Directory.CreateDirectory(@"C:\Stellar Water Point8");
           }
   
           . . .
       }
   }

10. In the Solution Explorer, in the Customers folder, double-click Details
11. Click an unoccupied area of the form to select it
12. In the Solution Explorer, click the Events button
13. In the Events section of the Properties window, double-click FormClosing
14. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Details : Form
        {
            public Details()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a valid account number of " +
                                    "a customer whose account you want to view.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients    = new List<Customer>();
                string strCustomers       = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers      = new FileInfo(strCustomers);
    
                string? strMeterNumber    = string.Empty;
    
                if (fiCustomers.Exists    == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text = client.AccountName;
                                txtAccountType.Text = client.AccountType;
                                strMeterNumber      = client.MeterNumber;
                                txtAddress.Text     = client.Address;
                                txtCity.Text        = client.City;
                                txtCounty.Text      = client.County;
                                txtState.Text       = client.State;
                                txtZIPCode.Text     = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Details_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.CustomerDetailsDisplaying == true)
                {
                    WaterDistribution.CustomerDetailsDisplaying = false;
                    Close();
                }
            }
        }
    }

15. In the Solution Explorer, double-click WaterDistribution.cs to display the primary form of the application
16. On the menu bar of the form, click Customers and, below it, double-click Customer Account Details...
17. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
    
            private void miCustomersCreate_Click(object sender, EventArgs e)
            {
                if (CustomerCreateDisplaying == false)
                {
                    customerCreate = new();
                    customerCreate.MdiParent = this;
                    customerCreate.Show();
    
                    CustomerCreateDisplaying = true;
                }
                else
                {
                    customerCreate.BringToFront();
                }
            }
    
            private void miCustomersDetails_Click(object sender, EventArgs e)
            {
                if (CustomerDetailsDisplaying == false)
                {
                    customerDetails = new();
                    customerDetails.MdiParent = this;
                    customerDetails.Show();
    
                    CustomerDetailsDisplaying = true;
                }
                else
                {
                    customerDetails.BringToFront();
                }
            }
        }
    }

18. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

19. On the main menu of the Stellar Water Point form, click Customers and click View Customers Accounts:

    

20. Again, on the main menu of the form, click Customers and click Customer Account Details:

    

21. In the Account # text, type 4086-938-4783
22. Click the Find Customer Account button:

    

23. Close the forms and return to your programming environment

Updating a Customer Account

.

Practical Learning: Updating a Customer Account

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Editor as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Button		btnFindCustomerAccount	&Find Customer Account
   Label			&Account Name:
   TextBox		txtAccountName
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000
   Button		btnFindWaterMeter	Find &Water Meter
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   ComboBox		cbxAccountsTypes		Items: OTH - Other BUS - General Business RES - Residential Household SGO - Social/Government/Non-Profit Organization UUO - Unidentified or Unclassified Type of Organization WAT - Water Intensive Business (Laudromat, Hair Salon, Restaurant, etc
   Label			&Address:
   TextBox		txtAddress
   Label			C&ity:
   TextBox		txtCity
   Label			C&ounty:
   TextBox		txtCounty
   Label			&State:
   TextBox		txtState
   Label			&ZIP-Code:
   MaskedTextBox		mtbZIPCode		Masked: Zip-Code
   Button		btnUpdateCustomerAccount	&Update Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. On the form, double-click the Find Customer Account button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to view.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text   = client.AccountName;
                               cbxAccountsTypes.Text = client.AccountType;
                               strMeterNumber        = client.MeterNumber;
                               txtAddress.Text       = client.Address;
                               txtCity.Text          = client.City;
                               txtCounty.Text        = client.County;
                               txtState.Text         = client.State;
                               mtbZIPCode.Text       = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Find Water Meter button
8. Implement the event as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to view.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               cbxAccountsTypes.Text = client.AccountType;
                               mtbMeterNumber.Text = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               mtbZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a number for a water meter.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               WaterMeter? meter = null;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               if (meter is null)
               {
                   MessageBox.Show("There is no water meter with that number in our system.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
           }
       }
   }

9. Return to the form and double-click the Update Customer Account button
10. Return to the form and double-click the Close button
11. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a valid account number of " +
                                    "a customer whose account you want to view.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text = client.AccountName;
                                cbxAccountsTypes.Text = client.AccountType;
                                mtbMeterNumber.Text = client.MeterNumber;
                                txtAddress.Text = client.Address;
                                txtCity.Text = client.City;
                                txtCounty.Text = client.County;
                                txtState.Text = client.State;
                                mtbZIPCode.Text = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must provide an account number of the customer " +
                                    "whose account you are creating. Then, click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        foreach (Customer client in clients)
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                client.AccountName   = txtAccountName.Text;
                                client.AccountType   = cbxAccountsTypes.Text;
                                client.MeterNumber   = mtbMeterNumber.Text;
                                client.Address       = txtAddress.Text;
                                client.City          = txtCity.Text;
                                client.County        = txtCounty.Text;
                                client.State         = txtState.Text;
                                client.ZIPCode       = mtbZIPCode.Text;
                            }
                        }
                    }
    
                    using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
                    {
                        xsCustomers.Serialize(twCustomers, clients);
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

12. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
13. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

14. In the Solution Explorer, in the Customers folder, double-click Editor
15. Click an unoccupied area of the form to select it
16. In the Solution Explorer, click the Events button
17. In the Events section of the Properties window, double-click FormClosing
18. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a valid account number of " +
                                    "a customer whose account you want to view.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text = client.AccountName;
                                cbxAccountsTypes.Text = client.AccountType;
                                mtbMeterNumber.Text = client.MeterNumber;
                                txtAddress.Text = client.Address;
                                txtCity.Text = client.City;
                                txtCounty.Text = client.County;
                                txtState.Text = client.State;
                                mtbZIPCode.Text = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a number for a water meter.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                WaterMeter? meter = null;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        meter = waterMeters.Find(m => m.MeterNumber == mtbMeterNumber.Text)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
    
                if (meter is null)
                {
                    MessageBox.Show("There is no water meter with that number in our system.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
            }
    
            private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbMeterNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must provide an account number of the customer " +
                                    "whose account you are creating. Then, click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        foreach (Customer client in clients)
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                client.AccountName   = txtAccountName.Text;
                                client.AccountType   = cbxAccountsTypes.Text;
                                client.MeterNumber   = mtbMeterNumber.Text;
                                client.Address       = txtAddress.Text;
                                client.City          = txtCity.Text;
                                client.County        = txtCounty.Text;
                                client.State         = txtState.Text;
                                client.ZIPCode       = mtbZIPCode.Text;
                            }
                        }
                    }
    
                    using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
                    {
                        xsCustomers.Serialize(twCustomers, clients);
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Editor_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.CustomerEditorDisplaying == true)
                {
                    WaterDistribution.CustomerEditorDisplaying = false;
                    Close();
                }
            }
        }
    }

19. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
20. On the menu bar of the form, click Water Meters and, below it, double-click Update Customer Account...
21. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
    
            private void miCustomersCreate_Click(object sender, EventArgs e)
            {
                if (CustomerCreateDisplaying == false)
                {
                    customerCreate = new();
                    customerCreate.MdiParent = this;
                    customerCreate.Show();
    
                    CustomerCreateDisplaying = true;
                }
                else
                {
                    customerCreate.BringToFront();
                }
            }
    
            private void miCustomersDetails_Click(object sender, EventArgs e)
            {
                if (CustomerDetailsDisplaying == false)
                {
                    customerDetails = new();
                    customerDetails.MdiParent = this;
                    customerDetails.Show();
    
                    CustomerDetailsDisplaying = true;
                }
                else
                {
                    customerDetails.BringToFront();
                }
            }
    
            private void miCustomersEditor_Click(object sender, EventArgs e)
            {
                if (CustomerEditorDisplaying == false)
                {
                    customerEditor = new();
                    customerEditor.MdiParent = this;
                    customerEditor.Show();
    
                    CustomerEditorDisplaying = true;
                }
                else
                {
                    customerEditor.BringToFront();
                }
            }
        }
    }

22. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

23. On the main menu of the central form of the application, click Customers and click View Customers Accounts

    

24. On the main menu of the central form of the application, click Customers and click Update Customer Account

    

25. In the Account # text, type 4086-938-4783
26. Click the Find Customer Account button
27. Change the values as follows:

    Account Name: Bernotte Doughnuts
    Meter #:      580-742-825 and click Find Water Meter
    Account Type: BUS	- General Business
    Address:      10103 Hexagon Drive
    City:         Winterstown
    County:       York
    State:        PA
    ZIP-Code:     17402-8828

    

28. Click the Update Customer Account button:

    

29. Close the forms and return to your programming environment

Deleting a Customer Account

.

Practical Learning: Deleting a Customer Account

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form(Windows Forms)...
2. In the Name text box, replace the string with Delete as the name of the form
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Button		btnFindCustomerAccount	&Find Customer Account
   Label			&Account Name:
   TextBox		txtAccountName		Enabled: False
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   TextBox		txtAccountsTypes		Enabled: False
   Label			&Address:
   TextBox		txtAddress		Enabled: False
   Label			C&ity:
   TextBox		txtCity		Enabled: False
   Label			C&ounty:
   TextBox		txtCounty		Enabled: False
   Label			&State:
   TextBox		txtState		Enabled: False
   Label			&ZIP-Code:
   TextBox		txtZIPCode		Enabled: False
   Button		btnDeleteCustomerAccount	&Delete Customer Account
   Button		btnClose	&Close

5. On the form, double-click the Find Customer Account button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Delete: Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to view.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Delete Customer Account button
8. Return to the form and double-click the Close button
9. Implement the events as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.Customers
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must provide the account number of " +
                                   "the customer to delete.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber      = client.MeterNumber;
                               txtAddress.Text     = client.Address;
                               txtCity.Text        = client.City;
                               txtCounty.Text      = client.County;
                               txtState.Text       = client.State;
                               txtZIPCode.Text     = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to remove.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       foreach(Customer client in clients)
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               clients.Remove(client);
                               break;
                           }
                       }
                   }
   
                   using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
                   {
                       xsCustomers.Serialize(twCustomers, clients);
                   }
               }
               
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
11. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
            public static bool          CustomerDeleteDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
            private Customers.Delete    customerDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
                CustomerDeleteDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
                customerDelete              = new Customers.Delete();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

12. In the Solution Explorer, in the Customers folder, double-click Delete
13. Click an unoccupied area of the form to select it
14. In the Solution Explorer, click the Events button
15. In the Events section of the Properties window, double-click FormClosing
16. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.Customers
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must provide the account number of " +
                                    "the customer to delete.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text = client.AccountName;
                                txtAccountType.Text = client.AccountType;
                                strMeterNumber = client.MeterNumber;
                                txtAddress.Text = client.Address;
                                txtCity.Text = client.City;
                                txtCounty.Text = client.County;
                                txtState.Text = client.State;
                                txtZIPCode.Text = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a valid account number of " +
                                    "a customer whose account you want to remove.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        foreach (Customer client in clients)
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                clients.Remove(client);
                                break;
                            }
                        }
                    }
    
                    using (TextWriter twCustomers = new StreamWriter(fiCustomers.FullName))
                    {
                        xsCustomers.Serialize(twCustomers, clients);
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Delete_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.CustomerDeleteDisplaying == true)
                {
                    WaterDistribution.CustomerDeleteDisplaying = false;
                    Close();
                }
            }
        }
    }

17. In the Solution Explorer, double-click WaterDistribution.cs to display the central form of the application
18. On the menu bar of the form, click Customers and, below it, double-click Delete Customer Account...
19. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
            public static bool          CustomerDeleteDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
            private Customers.Delete    customerDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
                CustomerDeleteDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
                customerDelete              = new Customers.Delete();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
    
            private void miCustomersCreate_Click(object sender, EventArgs e)
            {
                if (CustomerCreateDisplaying == false)
                {
                    customerCreate = new();
                    customerCreate.MdiParent = this;
                    customerCreate.Show();
    
                    CustomerCreateDisplaying = true;
                }
                else
                {
                    customerCreate.BringToFront();
                }
            }
    
            private void miCustomersDetails_Click(object sender, EventArgs e)
            {
                if (CustomerDetailsDisplaying == false)
                {
                    customerDetails = new();
                    customerDetails.MdiParent = this;
                    customerDetails.Show();
    
                    CustomerDetailsDisplaying = true;
                }
                else
                {
                    customerDetails.BringToFront();
                }
            }
    
            private void miCustomersEditor_Click(object sender, EventArgs e)
            {
                if (CustomerEditorDisplaying == false)
                {
                    customerEditor = new();
                    customerEditor.MdiParent = this;
                    customerEditor.Show();
    
                    CustomerEditorDisplaying = true;
                }
                else
                {
                    customerEditor.BringToFront();
                }
            }
    
            private void miCustomersDelete_Click(object sender, EventArgs e)
            {
                if (CustomerDeleteDisplaying == false)
                {
                    customerDelete = new();
                    customerDelete.MdiParent = this;
                    customerDelete.Show();
    
                    CustomerDeleteDisplaying = true;
                }
                else
                {
                    customerDelete.BringToFront();
                }
            }
        }
    }

20. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

21. On the main menu of the central form of the application, click Customers and click View Customers Accounts

    

22. On the main menu of the central form of the application, click Customers and click Delete Customer Account

    

23. In the Account # text box, type 4086-938-4783
24. Click the Find Customer Account button:

    

25. Click the Delete Customer Account button
26. Read the text on the message box.
    On the message box, click Yes
27. In the same way, delete one of the other two records
28. Close the forms and return to your programming environment
29. From the Windows Explorer, open the Customers.xml file
30. Replace the content of the file with the provided file
31. Save the file
32. Return to your programming environment

Water Bills

Introduction

.

Practical Learning: Starting Water Meters Issues

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. Type WaterBillManagement as the Name of the file
3. Click Add
4. Define the class as follows:

   namespace StellarWaterPoint31.Models
   {
       internal static class WaterBillManagement
       {
           internal static (double a, double b, double c) CalculateTiers(string acnt, double total)
           {
               (double tier1, double tier2, double tier3) results = (0.00, 0.00, 0.00);
   
               if (acnt == "RES")
               {
                   results.tier1 = total * 41.50 / 10000.00;
                   results.tier2 = total * 32.50 / 10000.00;
                   results.tier3 = total * 26.00 / 10000.00;
               }
               else if (acnt == "SGO")
               {
                   results.tier1 = total * 46.00 / 10000.00;
                   results.tier2 = total * 50.00 / 10000.00;
                   results.tier3 = total * 4.00  / 10000.00;
               }
               else if (acnt == "BUS")
               {
                   results.tier1 = total * 45.00 / 10000.00;
                   results.tier2 = total * 30.00 / 10000.00;
                   results.tier3 = total * 25.00 / 10000.00;
               }
               else if (acnt == "UUO")
               {
                   results.tier1 = total * 25.00 / 10000.00;
                   results.tier2 = total * 35.00 / 10000.00;
                   results.tier3 = total * 40.00 / 10000.00;
               }
               else if (acnt == "WAT")
               {
                   results.tier1 = total * 50.00 / 10000.00;
                   results.tier2 = total * 40.00 / 10000.00;
                   results.tier3 = total * 10.00 / 10000.00;
               }
               else
               {
                   results.tier1 = total * (48.00 / 10000.00);
                   results.tier2 = total * (32.00 / 10000.00);
                   results.tier3 = total * (20.00 / 10000.00);
               }
   
               return results;
           }
   
           internal static double CalculateSewerCharges(string acnt, double total)
           {
               double result;
   
               if (acnt == "RES")
               {
                   result = total * 6.826941 / 100.00;
               }
               else if (acnt == "SGO")
               {
                   result = total * 4.162522 / 100.00;
               }
               else if (acnt == "BUS")
               {
                   result = total * 8.315136 / 100.00;
               }
               else if (acnt == "UUO")
               {
                   result = total * 10.626147 / 100.00;
               }
               else if (acnt == "WAT")
               {
                   result = total * 12.025135 / 100.00;
               }
               else // if (acnt == "OTH")
               {
                   result = total * 9.202615 / 100.00;
               }
   
               return result;
           }
   
           internal static double CalculateEnvironmentCharges(string acnt, double total)
           {
               double result;
   
               switch (acnt)
               {
                   case "RES":
                       result = total * 0.022724;
                       break;
                   case "SGO":
                       result = total * 0.118242;
                       break;
                   case "BUS":
                       result = total * 0.161369;
                       break;
                   case "UUO":
                       result = total * 0.082477;
                       break;
                   case "WAT":
                       result = total * 0.413574;
                       break;
                   default:
                       result = total * 0.221842;
                       break;
               }
   
               return result;
           }
   
           internal static double CalculateServiceCharges(string acnt, double total)
           {
               switch (acnt)
               {
                   case "RES":
                       return total * 0.145748;
                   case "SGO":
                       return total * 0.102246;
                   case "BUS":
                       return total * 0.242627;
                   case "UUO":
                       return total * 0.186692;
                   case "WAT":
                       return total * 0.412628;
                   default:
                       return total * 0.210248;
               }
           }
   
           internal static double CalculateLocalTaxes(string acnt, double total) => acnt switch
           {
               "RES" => total * 0.031574,
               "SGO" => total * 0.035026,
               "BUS" => total * 0.122517,
               "UUO" => total * 0.105737,
               "WAT" => total * 0.153248,
               _     => total * 0.125148
           };
   
           internal static double CalculateStateTaxes(string acnt, double total) => acnt switch
           {
               "RES" => total * 0.01724,
               "SGO" => total * 0.008779,
               "BUS" => total * 0.042448,
               "UUO" => total * 0.067958,
               "WAT" => total * 0.081622,
               _     => total * 0.013746
           };
   
           internal static DateTime SetPaymentDueDate(string acnt, DateTime date)
           {
               TimeSpan tsPaymentDueDate = new TimeSpan(1, 0, 0, 0);
   
               if (acnt == "RES")
               {
                   tsPaymentDueDate = new TimeSpan(15, 0, 0, 0);
               }
               else if (acnt == "SGO")
               {
                   tsPaymentDueDate = new TimeSpan(20, 0, 0, 0);
               }
               else if (acnt == "BUS")
               {
                   tsPaymentDueDate = new TimeSpan(30, 0, 0, 0);
               }
               else if (acnt == "UUO")
               {
                   tsPaymentDueDate = new TimeSpan(25, 0, 0, 0);
               }
               else if (acnt == "WAT")
               {
                   tsPaymentDueDate = new TimeSpan(40, 0, 0, 0);
               }
               else
               {
                   tsPaymentDueDate = new TimeSpan(35, 0, 0, 0);
               }
   
               return date + tsPaymentDueDate;
           }
   
           internal static DateTime SetLatePaymentDueDate(string acnt, DateTime date)
           {
               switch (acnt)
               {
                   case "RES":
                       return date + new TimeSpan(30, 0, 0, 0);
                   case "SGO":
                       return date + new TimeSpan(40, 0, 0, 0);
                   case "BUS":
                       return date + new TimeSpan(50, 0, 0, 0);
                   case "UUO":
                       return date + new TimeSpan(60, 0, 0, 0);
                   case "WAT":
                       return date + new TimeSpan(65, 0, 0, 0);
                   default:
                       return date + new TimeSpan(45, 0, 0, 0);
               }
           }
   
           internal static double CalculateLateAmountDue(string acnt, double amt) => acnt switch
           {
               "RES" => amt + 8.95,
               "SGO" => amt + (amt / 4.575),
               "BUS" => amt + (amt / 12.315),
               "UUO" => amt + (amt / 7.425),
               "WAT" => amt + (amt / 15.225),
               _     => amt + (amt / 6.735)
           };
       }
   }

5. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
6. On the main menu, click Project -> Add Class...
7. Replace the name with WaterBill
8. Click Add
9. Change the code as follows:

   namespace StellarWaterPoint50.Models
   {
       public record WaterBill
       {
           public string?  BillNumber            { get; set; }
           public string?  AccountNumber         { get; set; }
           public DateTime MeterReadingStartDate { get; set; }
           public DateTime MeterReadingEndDate   { get; set; }
           public int      BillingDays           { get; set; }
           public int      CounterReadingStart   { get; set; }
           public int      CounterReadingEnd     { get; set; }
           public int      TotalHCF              { get; set; }
           public int      TotalGallons          { get; set; }
           public double   FirstTierConsumption  { get; set; }
           public double   SecondTierConsumption { get; set; }
           public double   LastTierConsumption   { get; set; }
           public double   WaterCharges          { get; set; }
           public double   SewerCharges          { get; set; }
           public double   EnvironmentCharges    { get; set; }
           public double   ServiceCharges        { get; set; }
           public double   TotalCharges          { get; set; }
           public double   LocalTaxes            { get; set; }
           public double   StateTaxes            { get; set; }
           public DateTime PaymentDueDate        { get; set; }
           public double   AmountDue             { get; set; }
           public DateTime LatePaymentDueDate    { get; set; }
           public double   LateAmountDue         { get; set; }
       }
   }

10. In the Solution Explorer, right-click StellarWaterPoint1 -> Add -> New Folder
11. Type WaterBills as the name of the folder

Displaying Water Bills

.

Practical Learning: Displaying Water Bills

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	TextAlign	Width
   colWaterBillId	Id		40
   colBillNumber	Bill #	Center	80
   colAccountSummary	Account Summary	Center	550
   colStartDate	Start Date	Center	150
   colEndDate	End Date	Center	150
   colBillingDays	Days	Center
   colCounterStart	Counter Start	Right	125
   colCounterEnd	Counter End	Right	125
   colTotalHCF	Total HCF	Right	100
   colGallons	Gallons	Right	95
   colPaymentDueDate	Pmt Due Date	Center	125
   colAmountDue	Amt Due	Right	90

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwWaterBills	FullRowSelect: True GridLines: True View: Details

9. Click an unoccupied area of the form to select it
10. In the Solution Explorer, click the Events button
11. In the Events section of the Properties window, double-click Activated
12. Change the document as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
                    }
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        int counter = 1;
    
                        lvwWaterBills.Items.Clear();
    
                        foreach (WaterBill bill in bills)
                        {
                            ListViewItem lviWaterBill = new ListViewItem(counter++.ToString());
    
                            lviWaterBill.SubItems.Add(bill.BillNumber!.ToString());
    
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == bill.AccountNumber);
    
                                                    foreach (Customer cust in customer)
                                                  {
                            lviWaterBill.SubItems.Add(bill.AccountNumber + " - " +
                                                          cust.AccountName +
                                                          ", Type: " + cust.AccountType![..3] +
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            lviWaterBill.SubItems.Add(bill.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(bill.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(bill.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(bill.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(bill.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(bill.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
        }
    }

13. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
14. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
            public static bool          CustomerDeleteDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
            private Customers.Delete    customerDelete;
    
            public static bool          WaterBillsDisplaying;
            private WaterBills.Central  waterBills;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
                CustomerDeleteDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
                customerDelete              = new Customers.Delete();
    
                WaterBillsDisplaying        = false;
                waterBills                  = new WaterBills.Central();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

15. In the Solution Explorer, in the WaterBills folder, double-click Central (make sure the form is selected)
16. In the Events section of the Properties window, double-click FormClosing
17. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
                    }
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        int counter = 1;
    
                        lvwWaterBills.Items.Clear();
    
                        foreach (WaterBill bill in bills)
                        {
                            ListViewItem lviWaterBill = new ListViewItem(counter++.ToString());
    
                            lviWaterBill.SubItems.Add(bill.BillNumber!.ToString());
    
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == bill.AccountNumber);
    
                                                    foreach (Customer cust in customer)
                                                  {
                            lviWaterBill.SubItems.Add(bill.AccountNumber + " - " +
                                                          cust.AccountName +
                                                          ", Type: " + cust.AccountType![..3] +
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            lviWaterBill.SubItems.Add(bill.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(bill.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(bill.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(bill.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(bill.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(bill.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(bill.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Activated(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void Central_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterBillsDisplaying == true)
                {
                    WaterDistribution.WaterBillsDisplaying = false;
                    Close();
                }
            }
        }
    }

18. In the Solution Explorer, double-click WaterDistribution.cs to display the form
19. On the menu that was designed on the form, click Water Bills and, below it, double-click View Water Bills...
20. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
            public static bool CustomerCreateDisplaying;
            public static bool CustomerDetailsDisplaying;
            public static bool CustomerEditorDisplaying;
            public static bool CustomerDeleteDisplaying;
    
            private Customers.Central customers;
            private Customers.Create customerCreate;
            private Customers.Details customerDetails;
            private Customers.Editor customerEditor;
            private Customers.Delete customerDelete;
    
            public static bool WaterBillsDisplaying;
            private WaterBills.Central waterBills;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
                CustomerDetailsDisplaying = false;
                CustomerEditorDisplaying = false;
                CustomerDeleteDisplaying = false;
    
                customers = new Customers.Central();
                customerCreate = new Customers.Create();
                customerDetails = new Customers.Details();
                customerEditor = new Customers.Editor();
                customerDelete = new Customers.Delete();
    
                WaterBillsDisplaying = false;
                waterBills = new WaterBills.Central();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
            private void miViewWaterBills_Click(object sender, EventArgs e)
            {
                if(WaterBillsDisplaying == false)
                {
                    waterBills = new WaterBills.Central();
    
                    waterBills.MdiParent = this;
                    waterBills.Show();
    
                    WaterBillsDisplaying = true;
                }
                else
                {
                    waterBills.BringToFront();
                }
            }
        }
    }

A Water Bill Record

.

Practical Learning: Creating a Water Bill Record

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form(Windows Forms)...
2. Type Create
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   GroupBox		Customer Information
   Label		&Account #:
   MaskedTextBox			mtbAccountNumber	Mask: 0000-000-0000
   Button		Find Customer &Account	btnFindCustomerAccount
   Label		Account Name:
   TextBox			txtAccountName
   Label		Account Type:
   TextBox			txtAccountType
   Label		Address:
   TextBox			txtAddress
   TextBox			txtCity
   TextBox			txtCounty
   TextBox			txtState
   TextBox			txtZIPCode
   Label		___________________________
   Label		Meter Details:
   TextBox			txtMeterDetails
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Date Time Picker			dtpMeterReadingStartDate
   Label		Meter Reading &End Date:
   Date Time Picker			dtpMeterReadingEndDate
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd
   Button		&Evaluate Water Bill	btnEvaluateWaterBill	Times New Roman, 24pt, style=Bold
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays
   Label		Total HCF:
   TextBox			txtTotalHCF
   Label		Total Gallons:
   TextBox			txtTotalGallons
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption
   Label		Second Tier:
   TextBox			txtSecondTierConsumption
   Label		Last Tier:
   TextBox			txtLastTierConsumption
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges
   Label		Sewer Charges:
   TextBox			txtSewerCharges
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges
   Label		Service Charges:
   TextBox			txtServiceCharges
   Label		Total Charges:
   TextBox			txtTotalCharges
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes
   Label		State Taxes:
   TextBox			txtStateTaxes
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate
   Label		Amount Due:
   TextBox			txtAmountDue
   Label		Late Payment Due Date:
   Date Time Picker			dtpLatePaymentDueDate
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		Save Water Bill	btnSaveWaterBill
   Button		&Close	btnClose

5. On the form, double-click the Find Customer Account button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type an account number for the customer whose record you want to find.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               Customer? client = null;
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       client = clients.Find(cl => cl.AccountNumber == mtbAccountNumber.Text)!;
   
                       if (client is not null)
                       {
                           txtAccountName.Text  = client.AccountName;
                           strMeterNumber       = client.MeterNumber;
                           txtAccountType.Text  = client.AccountType;
                           txtAddress.Text      = client.Address;
                           txtCity.Text         = client.City;
                           txtCounty.Text       = client.County;
                           txtState.Text        = client.State;
                           txtZIPCode.Text      = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   WaterMeter? meter = null;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                   XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
                   FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                       {
                           waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                           meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                           if (meter is not null)
                           {
                               txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                           }
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Meter Reading End Date date time picker to generate its Value Changed event
8. Implement the event as follows:

   using System.Data;
   using Microsoft.Data.SqlClient;
   
   namespace StellarWaterPoint31.WaterBills
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               . . .
           }
   
           private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
           {
               TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
   
               txtBillingDays.Text = (tsDays.Days + 1).ToString();
           }
       }
   }

9. Return to the form and double-click the Evaluate Water Bill button
10. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type an account number for the customer whose record you want to find.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                Customer? client = null;
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        client = clients.Find(cl => cl.AccountNumber == mtbAccountNumber.Text)!;
    
                        if (client is not null)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber      = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text     = client.Address;
                            txtCity.Text        = client.City;
                            txtCounty.Text      = client.County;
                            txtState.Text       = client.State;
                            txtZIPCode.Text     = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    WaterMeter? meter = null;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                    XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                    FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                        {
                            waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                            meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                            if (meter is not null)
                            {
                                txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                            }
                        }
                    }
                }
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0d, counterEnd = 0d;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption = counterEnd - counterStart;
                double gallons = consumption * 748.05;
                string strAccountType = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges           = tiers.first + tiers.second + tiers.last;
                double sewerCharges           = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges             = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges             = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges           = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes             = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes             = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue                 = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text              = consumption.ToString();
                txtTotalGallons.Text          = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text  = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text   = tiers.last.ToString("F");
                txtWaterCharges.Text          = waterCharges.ToString("F");
                txtSewerCharges.Text          = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text    = envCharges.ToString("F");
                txtServiceCharges.Text        = srvCharges.ToString("F");
                txtTotalCharges.Text          = totalCharges.ToString("F");
                txtLocalTaxes.Text            = localTaxes.ToString("F");
                txtStateTaxes.Text            = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value       = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text             = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value   = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text         = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
        }
    }

11. Return to the form and double-click the Save Water Bill button
12. Return to the form and double-click the &Close button
13. Change the document as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type an account number for the customer whose record you want to find.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                Customer? client = null;
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        client = clients.Find(cl => cl.AccountNumber == mtbAccountNumber.Text)!;
    
                        if (client is not null)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            txtZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    WaterMeter? meter = null;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                    XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                    FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                        {
                            waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                            meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                            if (meter is not null)
                            {
                                txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                            }
                        }
                    }
                }
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0d, counterEnd = 0d;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption = counterEnd - counterStart;
                double gallons = consumption * 748.05;
                string strAccountType = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges = tiers.first + tiers.second + tiers.last;
                double sewerCharges = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text = consumption.ToString();
                txtTotalGallons.Text = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text = tiers.last.ToString("F");
                txtWaterCharges.Text = waterCharges.ToString("F");
                txtSewerCharges.Text = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text = envCharges.ToString("F");
                txtServiceCharges.Text = srvCharges.ToString("F");
                txtTotalCharges.Text = totalCharges.ToString("F");
                txtLocalTaxes.Text = localTaxes.ToString("F");
                txtStateTaxes.Text = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
    
            private void btnSaveWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
                    }
                }
    
                WaterBill bill = new()
                {
                    BillNumber = txtBillNumber.Text,
                    AccountNumber = mtbAccountNumber.Text,
                    MeterReadingStartDate = dtpMeterReadingStartDate.Value,
                    MeterReadingEndDate = dtpMeterReadingEndDate.Value,
                    BillingDays = int.Parse(txtBillingDays.Text),
                    CounterReadingStart = int.Parse(txtCounterReadingStart.Text),
                    CounterReadingEnd = int.Parse(txtCounterReadingEnd.Text),
                    TotalHCF = int.Parse(txtTotalHCF.Text),
                    TotalGallons = int.Parse(txtTotalGallons.Text),
                    FirstTierConsumption = double.Parse(txtFirstTierConsumption.Text),
                    SecondTierConsumption = double.Parse(txtSecondTierConsumption.Text),
                    LastTierConsumption = double.Parse(txtLastTierConsumption.Text),
                    WaterCharges = double.Parse(txtWaterCharges.Text),
                    SewerCharges = double.Parse(txtSewerCharges.Text),
                    EnvironmentCharges = double.Parse(txtEnvironmentCharges.Text),
                    ServiceCharges = double.Parse(txtServiceCharges.Text),
                    TotalCharges = double.Parse(txtTotalCharges.Text),
                    LocalTaxes = double.Parse(txtLocalTaxes.Text),
                    StateTaxes = double.Parse(txtStateTaxes.Text),
                    PaymentDueDate = dtpPaymentDueDate.Value,
                    AmountDue = double.Parse(txtAmountDue.Text),
                    LatePaymentDueDate = dtpLatePaymentDueDate.Value,
                    LateAmountDue = double.Parse(txtLateAmountDue.Text)
                };
    
                bills.Add(bill);
    
                using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                {
                    xsWaterBills.Serialize(twWaterBills, bills);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

14. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
15. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool          WaterMetersDisplaying;
            public static bool          WaterMeterCreateDisplaying;
            public static bool          WaterMeterDetailsDisplaying;
            public static bool          WaterMeterEditorDisplaying;
            public static bool          WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create  waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor  waterMeterEditor;
            private WaterMeters.Delete  waterMeterDelete;
    
            public static bool          CustomersDisplaying;
            public static bool          CustomerCreateDisplaying;
            public static bool          CustomerDetailsDisplaying;
            public static bool          CustomerEditorDisplaying;
            public static bool          CustomerDeleteDisplaying;
    
            private Customers.Central   customers;
            private Customers.Create    customerCreate;
            private Customers.Details   customerDetails;
            private Customers.Editor    customerEditor;
            private Customers.Delete    customerDelete;
    
            public static bool          WaterBillsDisplaying;
            public static bool          WaterBillCreateDisplaying;
    
            private WaterBills.Central  waterBills;
            private WaterBills.Create   waterBillCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
                CustomerDetailsDisplaying = false;
                CustomerEditorDisplaying = false;
                CustomerDeleteDisplaying = false;
    
                customers = new Customers.Central();
                customerCreate = new Customers.Create();
                customerDetails = new Customers.Details();
                customerEditor = new Customers.Editor();
                customerDelete = new Customers.Delete();
    
                WaterBillsDisplaying = false;
                waterBills = new WaterBills.Central();
    
                WaterBillsDisplaying = false;
                WaterBillCreateDisplaying = false;
                waterBills = new WaterBills.Central();
                waterBillCreate = new WaterBills.Create();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
            
            . . .
        }
    }

16. In the Solution Explorer, in the WaterBills folder, double-click Create
17. Click an unoccupied area of the form to select it
18. In the Solution Explorer, click the Events button
19. In the Events section of the Properties window, double-click FormClosing
20. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type an account number for the customer whose record you want to find.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                Customer? client = null;
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        client = clients.Find(cl => cl.AccountNumber == mtbAccountNumber.Text)!;
    
                        if (client is not null)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            txtZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    WaterMeter? meter = null;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                    XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                    FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                        {
                            waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                            meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                            if (meter is not null)
                            {
                                txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                            }
                        }
                    }
                }
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0d, counterEnd = 0d;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption = counterEnd - counterStart;
                double gallons = consumption * 748.05;
                string strAccountType = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges = tiers.first + tiers.second + tiers.last;
                double sewerCharges = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text = consumption.ToString();
                txtTotalGallons.Text = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text = tiers.last.ToString("F");
                txtWaterCharges.Text = waterCharges.ToString("F");
                txtSewerCharges.Text = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text = envCharges.ToString("F");
                txtServiceCharges.Text = srvCharges.ToString("F");
                txtTotalCharges.Text = totalCharges.ToString("F");
                txtLocalTaxes.Text = localTaxes.ToString("F");
                txtStateTaxes.Text = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
    
            private void btnSaveWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
                    }
                }
    
                WaterBill bill = new()
                {
                    BillNumber = txtBillNumber.Text,
                    AccountNumber = mtbAccountNumber.Text,
                    MeterReadingStartDate = dtpMeterReadingStartDate.Value,
                    MeterReadingEndDate = dtpMeterReadingEndDate.Value,
                    BillingDays = int.Parse(txtBillingDays.Text),
                    CounterReadingStart = int.Parse(txtCounterReadingStart.Text),
                    CounterReadingEnd = int.Parse(txtCounterReadingEnd.Text),
                    TotalHCF = int.Parse(txtTotalHCF.Text),
                    TotalGallons = int.Parse(txtTotalGallons.Text),
                    FirstTierConsumption = double.Parse(txtFirstTierConsumption.Text),
                    SecondTierConsumption = double.Parse(txtSecondTierConsumption.Text),
                    LastTierConsumption = double.Parse(txtLastTierConsumption.Text),
                    WaterCharges = double.Parse(txtWaterCharges.Text),
                    SewerCharges = double.Parse(txtSewerCharges.Text),
                    EnvironmentCharges = double.Parse(txtEnvironmentCharges.Text),
                    ServiceCharges = double.Parse(txtServiceCharges.Text),
                    TotalCharges = double.Parse(txtTotalCharges.Text),
                    LocalTaxes = double.Parse(txtLocalTaxes.Text),
                    StateTaxes = double.Parse(txtStateTaxes.Text),
                    PaymentDueDate = dtpPaymentDueDate.Value,
                    AmountDue = double.Parse(txtAmountDue.Text),
                    LatePaymentDueDate = dtpLatePaymentDueDate.Value,
                    LateAmountDue = double.Parse(txtLateAmountDue.Text)
                };
    
                bills.Add(bill);
    
                using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                {
                    xsWaterBills.Serialize(twWaterBills, bills);
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
    
            private void Create_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterBillCreateDisplaying == true)
                {
                    WaterDistribution.WaterBillCreateDisplaying = false;
                    Close();
                }
            }
        }
    }

21. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
22. On the menu that was designed on the form, click Water Bills and, below it, double-click Process Water Bill...
23. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
            public static bool CustomerCreateDisplaying;
            public static bool CustomerDetailsDisplaying;
            public static bool CustomerEditorDisplaying;
            public static bool CustomerDeleteDisplaying;
    
            private Customers.Central customers;
            private Customers.Create customerCreate;
            private Customers.Details customerDetails;
            private Customers.Editor customerEditor;
            private Customers.Delete customerDelete;
    
            public static bool WaterBillsDisplaying;
            public static bool WaterBillCreateDisplaying;
    
            private WaterBills.Central waterBills;
            private WaterBills.Create  waterBillCreate;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
                CustomerDetailsDisplaying = false;
                CustomerEditorDisplaying = false;
                CustomerDeleteDisplaying = false;
    
                customers = new Customers.Central();
                customerCreate = new Customers.Create();
                customerDetails = new Customers.Details();
                customerEditor = new Customers.Editor();
                customerDelete = new Customers.Delete();
    
                WaterBillsDisplaying = false;
                WaterBillCreateDisplaying = false;
                waterBills = new WaterBills.Central();
                waterBillCreate = new WaterBills.Create();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
            private void miWaterBillsCreate_Click(object sender, EventArgs e)
            {
                if (WaterBillCreateDisplaying == false)
                {
                    waterBillCreate = new WaterBills.Create();
    
                    waterBillCreate.MdiParent = this;
                    waterBillCreate.Show();
    
                    WaterBillCreateDisplaying = true;
                }
                else
                {
                    waterBillCreate.BringToFront();
                }
            }
        }
    }

24. To execute, on the main menu, click Debug -> Start Without Debugging:

    

25. On the main menu, click Water Bills and click View Water Bills...:

    

26. On the main menu, click Water Bills and click Process Water Bill...:

    

27. Enter the following values in the indicated text boxes or select the date values. Then click Find Customer Account, followed by Evaluate Water Bill, followed by Save Water Bill:

    

    

    Water Bill #	Account #	Reading Start Date	Reading End Date	Counter Reading Start	Counter Reading End
    451474	2068-258-9486	01/11/2010	04/12/2010	103943	103956
    923633	5293-957-3395	01/17/2010	08/18/2010	256945	256972
    917829	9279-570-8394	02/15/2010	05/14/2010	5205	5222
    202666	6986-829-3741	03/08/2010	06/06/2010	5679	5690

    

28. Close the forms and return to your programming environment

Viewing the Details of a Water Bill

.

Practical Learning: Viewing the Details of a Water Bill

1. To create a form, in the Solution Explorer, right-click the WaterBills folder -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   Button		&Find Water Bill	btnFindWaterBill
   GroupBox		Customer Information
   Label		&Account #:
   TextBox			txtAccountNumber	Enabled: False
   Label		Account Name:
   TextBox			txtAccountName	Enabled: False
   Label		Account Type:
   TextBox			txtAccountType	Enabled: False
   Label		Address:		Enabled: False
   TextBox			txtAddress	Enabled: False
   TextBox			txtCity
   TextBox			txtCounty	Enabled: False
   TextBox			txtState	Enabled: False
   TextBox			txtZIPCode	Enabled: False
   Label		______________________
   Label		Meter Details:
   TextBox			txtMeterDetails	Enabled: False
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Text Box			txtMeterReadingStartDate	Enabled: False
   Label		Meter Reading &End Date:
   Text Box			txtMeterReadingEndDate	Enabled: False
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart	Enabled: False
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd	Enabled: False
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays	Enabled: False
   Label		Total HCF:
   TextBox			txtTotalHCF	Enabled: False
   Label		Total Gallons:
   TextBox			txtTotalGallons	Enabled: False
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption	Enabled: False
   Label		Second Tier:
   TextBox			txtSecondTierConsumption	Enabled: False
   Label		Last Tier:
   TextBox			txtLastTierConsumption	Enabled: False
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges	Enabled: False
   Label		Sewer Charges:
   TextBox			txtSewerCharges	Enabled: False
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges	Enabled: False
   Label		Service Charges:
   TextBox			txtServiceCharges	Enabled: False
   Label		Total Charges:
   TextBox			txtTotalCharges	Enabled: False
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes	Enabled: False
   Label		State Taxes:
   TextBox			txtStateTaxes	Enabled: False
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate	Enabled: False
   Label		Amount Due:
   TextBox			txtAmountDue	Enabled: False
   Label		Late Payment Due Date:
   Text Box			txtLatePaymentDueDate	Enabled: False
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		&Close	btnClose

5. On the form, double-click the Find Water Bill button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(txtBillNumber.Text))
               {
                   MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
               XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
   
                       IEnumerable<WaterBill> invoices = bills.Where(invoice => invoice.BillNumber == txtBillNumber.Text);
   
                       foreach (WaterBill bill in invoices)
                       {
                           txtAccountNumber.Text = bill.AccountNumber;
                           txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                           txtMeterReadingEndDate.Text = bill.MeterReadingEndDate.ToShortDateString();
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           txtPaymentDueDate.Text = bill.PaymentDueDate.ToShortDateString();
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           txtLatePaymentDueDate.Text = bill.LatePaymentDueDate.ToLongDateString();
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                       ;
                   }
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == txtAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
9. Change the document as follows:

   namespace StellarWaterPoint50
   {
       public partial class WaterDistribution : Form
       {
           public static bool WaterMetersDisplaying;
           public static bool WaterMeterCreateDisplaying;
           public static bool WaterMeterDetailsDisplaying;
           public static bool WaterMeterEditorDisplaying;
           public static bool WaterMeterDeleteDisplaying;
   
           private WaterMeters.Central waterMeters;
           private WaterMeters.Create waterMeterCreate;
           private WaterMeters.Details waterMeterDetails;
           private WaterMeters.Editor waterMeterEditor;
           private WaterMeters.Delete waterMeterDelete;
   
           public static bool CustomersDisplaying;
           public static bool CustomerCreateDisplaying;
           public static bool CustomerDetailsDisplaying;
           public static bool CustomerEditorDisplaying;
           public static bool CustomerDeleteDisplaying;
   
           private Customers.Central customers;
           private Customers.Create customerCreate;
           private Customers.Details customerDetails;
           private Customers.Editor customerEditor;
           private Customers.Delete customerDelete;
   
           public static bool WaterBillsDisplaying;
           public static bool WaterBillCreateDisplaying;
           public static bool WaterBillDetailsDisplaying;
   
           private WaterBills.Central waterBills;
           private WaterBills.Create  waterBillCreate;
           private WaterBills.Details waterBillDetails;
   
           public WaterDistribution()
           {
               InitializeComponent();
   
               WaterMetersDisplaying = false;
               WaterMeterCreateDisplaying = false;
               WaterMeterDetailsDisplaying = false;
               WaterMeterEditorDisplaying = false;
               WaterMeterDeleteDisplaying = false;
   
               waterMeters = new WaterMeters.Central();
               waterMeterCreate = new WaterMeters.Create();
               waterMeterDetails = new WaterMeters.Details();
               waterMeterEditor = new WaterMeters.Editor();
               waterMeterDelete = new WaterMeters.Delete();
   
               CustomersDisplaying = false;
               CustomerCreateDisplaying = false;
               CustomerDetailsDisplaying = false;
               CustomerEditorDisplaying = false;
               CustomerDeleteDisplaying = false;
   
               customers = new Customers.Central();
               customerCreate = new Customers.Create();
               customerDetails = new Customers.Details();
               customerEditor = new Customers.Editor();
               customerDelete = new Customers.Delete();
   
               WaterBillsDisplaying = false;
               WaterBillCreateDisplaying = false;
               WaterBillDetailsDisplaying = false;
   
               waterBills = new WaterBills.Central();
               waterBillCreate = new WaterBills.Create();
               waterBillDetails = new WaterBills.Details();
           }
   
           private void WaterDistribution_Load(object sender, EventArgs e)
           {
               Directory.CreateDirectory(@"C:\Stellar Water Point8");
           }
   
           . . .
       }
   }

10. In the Solution Explorer, in the WaterBills folder, double-click Details
11. Click an unoccupied area of the form to select it
12. In the Solution Explorer, click the Events button
13. In the Events section of the Properties window, double-click FormClosing
14. Implement the events as follows:

    using StellarWaterPoint50.Models;
    using System.Xml.Serialization;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Details : Form
        {
            public Details()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void Details_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterBillDetailsDisplaying == true)
                {
                    WaterDistribution.WaterBillDetailsDisplaying = false;
                    Close();
                }
            }
        }
    }

15. In the Solution Explorer, double-click WaterDistribution.cs to display the primary form of the application
16. On the menu bar of the form, click Water Bills and, below it, double-click Water Bill Details...
17. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            . . .
    
            private WaterBills.Central waterBills;
            private WaterBills.Create waterBillCreate;
            private WaterBills.Details waterBillDetails;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                . . .
    
                WaterBillsDisplaying = false;
                WaterBillCreateDisplaying = false;
                WaterBillDetailsDisplaying = false;
    
                waterBills = new WaterBills.Central();
                waterBillCreate = new WaterBills.Create();
                waterBillDetails = new WaterBills.Details();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
            private void miWaterBillsCreate_Click(object sender, EventArgs e)
            {
                if (WaterBillCreateDisplaying == false)
                {
                    waterBillCreate = new WaterBills.Create();
    
                    waterBillCreate.MdiParent = this;
                    waterBillCreate.Show();
    
                    WaterBillCreateDisplaying = true;
                }
                else
                {
                    waterBillCreate.BringToFront();
                }
            }
    
            private void miWaterBillsDetails_Click(object sender, EventArgs e)
            {
                if (WaterBillDetailsDisplaying == false)
                {
                    waterBillDetails = new();
                    waterBillDetails.MdiParent = this;
                    waterBillDetails.Show();
    
                    WaterBillDetailsDisplaying = true;
                }
                else
                {
                    waterBillDetails.BringToFront();
                }
            }
        }
    }

18. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

19. On the main menu of the Stellar Water Point form, click Water Bills and click View Water Bills:

    

20. Again, on the main menu of the form, click Water Bills and click Water Bill Details:

    

21. In the Water Bill # text box, type 917829
22. Click the Find Water Bill button:

    

23. Close the forms and return to your programming environment

Updating a Water Bill

.

Practical Learning: Updating a Customer Account

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Editor as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   Button		&Find Water Bill	btnFindWaterBill
   GroupBox		Customer Information
   Label		&Account #:
   MaskedTextBox			mtbAccountNumber	Mask: 0000-000-0000
   Button		Find Customer &Account	btnFindCustomerAccount
   Label		Account Name:
   TextBox			txtAccountName
   Label		Account Type:
   TextBox			txtAccountType
   Label		Address:
   TextBox			txtAddress
   TextBox			txtCity
   TextBox			txtCounty
   TextBox			txtState
   TextBox			txtZIPCode
   Label		___________________________
   Label		Meter Details:
   TextBox			txtMeterDetails
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Date Time Picker			dtpMeterReadingStartDate
   Label		Meter Reading &End Date:
   Date Time Picker			dtpMeterReadingEndDate
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd
   Button		&Evaluate Water Bill	btnEvaluateWaterBill	Times New Roman, 24pt, style=Bold
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays
   Label		Total HCF:
   TextBox			txtTotalHCF
   Label		Total Gallons:
   TextBox			txtTotalGallons
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption
   Label		Second Tier:
   TextBox			txtSecondTierConsumption
   Label		Last Tier:
   TextBox			txtLastTierConsumption
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges
   Label		Sewer Charges:
   TextBox			txtSewerCharges
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges
   Label		Service Charges:
   TextBox			txtServiceCharges
   Label		Total Charges:
   TextBox			txtTotalCharges
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes
   Label		State Taxes:
   TextBox			txtStateTaxes
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate
   Label		Amount Due:
   TextBox			txtAmountDue
   Label		Late Payment Due Date:
   Date Time Picker			dtpLatePaymentDueDate
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		Save Water Bill	btnSaveWaterBill
   Button		&Close	btnClose

5. On the form, double-click the Find Water Bill button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(txtBillNumber.Text))
               {
                   MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
               XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
   
                       IEnumerable<WaterBill> invoices = bills.Where(invoice => invoice.BillNumber == txtBillNumber.Text);
   
                       foreach (WaterBill bill in invoices)
                       {
                           mtbAccountNumber.Text = bill.AccountNumber;
                           dtpMeterReadingStartDate.Value = bill.MeterReadingStartDate;
                           dtpMeterReadingEndDate.Value = bill.MeterReadingEndDate;
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           dtpPaymentDueDate.Value = bill.PaymentDueDate;
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           dtpLatePaymentDueDate.Value = bill.LatePaymentDueDate;
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                       ;
                   }
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Find Customer Account button
8. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               . . .
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
   
               if (string.IsNullOrEmpty(strActual))
               {
                   MessageBox.Show("You must type a valid account number of " +
                                   "a customer whose account you want to view.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == mtbAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

9. Return to the form and double-click the Meter Reading End Date date time picker to generate its Value Changed event
10. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays     = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
        }
    }

11. Return to the form and double-click the Evaluate Water Bill button
12. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0d, counterEnd = 0d;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption = counterEnd - counterStart;
                double gallons = consumption * 748.05;
                string strAccountType = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges = tiers.first + tiers.second + tiers.last;
                double sewerCharges = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text = consumption.ToString();
                txtTotalGallons.Text = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text = tiers.last.ToString("F");
                txtWaterCharges.Text = waterCharges.ToString("F");
                txtSewerCharges.Text = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text = envCharges.ToString("F");
                txtServiceCharges.Text = srvCharges.ToString("F");
                txtTotalCharges.Text = totalCharges.ToString("F");
                txtLocalTaxes.Text = localTaxes.ToString("F");
                txtStateTaxes.Text = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
        }
    }

13. Return to the form and double-click the Update Water Bill button
14. Implement the event as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnUpdateWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to update.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strAccountNumber = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if(string.IsNullOrEmpty(strAccountNumber) | string.IsNullOrEmpty(txtAccountName.Text))
                {
                    MessageBox.Show("You must provide an account number of the customer " +
                                    "whose water bill you are trying to update. " +
                                    "After providing the account number, click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        foreach(WaterBill bill in bills)
                        {
                            if(bill.BillNumber == txtBillNumber.Text)
                            {
                                bill.AccountNumber = mtbAccountNumber.Text;
                                bill.MeterReadingStartDate = dtpMeterReadingStartDate.Value;
                                bill.MeterReadingEndDate = dtpMeterReadingEndDate.Value;
                                bill.BillingDays = int.Parse(txtBillingDays.Text);
                                bill.CounterReadingStart = int.Parse(txtCounterReadingStart.Text);
                                bill.CounterReadingEnd = int.Parse(txtCounterReadingEnd.Text);
                                bill.TotalHCF = int.Parse(txtTotalHCF.Text);
                                bill.TotalGallons = int.Parse(txtTotalGallons.Text);
                                bill.FirstTierConsumption = double.Parse(txtFirstTierConsumption.Text);
                                bill.SecondTierConsumption = double.Parse(txtSecondTierConsumption.Text);
                                bill.LastTierConsumption = double.Parse(txtLastTierConsumption.Text);
                                bill.WaterCharges = double.Parse(txtWaterCharges.Text);
                                bill.SewerCharges = double.Parse(txtSewerCharges.Text);
                                bill.EnvironmentCharges = double.Parse(txtEnvironmentCharges.Text);
                                bill.ServiceCharges = double.Parse(txtServiceCharges.Text);
                                bill.TotalCharges = double.Parse(txtTotalCharges.Text);
                                bill.LocalTaxes = double.Parse(txtLocalTaxes.Text);
                                bill.StateTaxes = double.Parse(txtStateTaxes.Text);
                                bill.PaymentDueDate = dtpPaymentDueDate.Value;
                                bill.AmountDue = double.Parse(txtAmountDue.Text);
                                bill.LatePaymentDueDate = dtpLatePaymentDueDate.Value;
                                bill.LateAmountDue = double.Parse(txtLateAmountDue.Text);
                            }
                        }
                    }
    
                    using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                    {
                        xsWaterBills.Serialize(twWaterBills, bills);
                    }
                }
    
                Close();
            }
        }
    }

15. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
16. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
            public static bool CustomerCreateDisplaying;
            public static bool CustomerDetailsDisplaying;
            public static bool CustomerEditorDisplaying;
            public static bool CustomerDeleteDisplaying;
    
            private Customers.Central customers;
            private Customers.Create customerCreate;
            private Customers.Details customerDetails;
            private Customers.Editor customerEditor;
            private Customers.Delete customerDelete;
    
            public static bool WaterBillsDisplaying;
            public static bool WaterBillCreateDisplaying;
            public static bool WaterBillDetailsDisplaying;
            public static bool WaterBillEditorDisplaying;
    
            private WaterBills.Central waterBills;
            private WaterBills.Create  waterBillCreate;
            private WaterBills.Details waterBillDetails;
            private WaterBills.Editor  waterBillEditor;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
                CustomerDetailsDisplaying = false;
                CustomerEditorDisplaying = false;
                CustomerDeleteDisplaying = false;
    
                customers = new Customers.Central();
                customerCreate = new Customers.Create();
                customerDetails = new Customers.Details();
                customerEditor = new Customers.Editor();
                customerDelete = new Customers.Delete();
    
                WaterBillsDisplaying = false;
                WaterBillCreateDisplaying = false;
                WaterBillDetailsDisplaying = false;
                WaterBillEditorDisplaying = false;
    
                waterBills = new WaterBills.Central();
                waterBillCreate = new WaterBills.Create();
                waterBillDetails = new WaterBills.Details();
                waterBillEditor = new WaterBills.Editor();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
        }
    }

17. In the Solution Explorer, in the WaterBills folder, double-click Editor
18. Click an unoccupied area of the form to select it
19. In the Solution Explorer, click the Events button
20. In the Events section of the Properties window, double-click FormClosing
21. Return to the Editor form and double-click the Close button
22. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills       = string.Empty;
                List<WaterBill> bills      = new List<WaterBill>();
                string fileWaterBills      = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills      = new FileInfo(fileWaterBills);
    
                if(fiWaterBills.Exists     == true)
                {
                    using(TextReader trWaterBills          = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        IEnumerable<WaterBill> invoices    = bills.Where(invoice => invoice.BillNumber == txtBillNumber.Text);
    
                        foreach (WaterBill bill in invoices)
                        {
                            mtbAccountNumber.Text          = bill.AccountNumber;
                            dtpMeterReadingStartDate.Value = bill.MeterReadingStartDate;
                            dtpMeterReadingEndDate.Value   = bill.MeterReadingEndDate;
                            txtBillingDays.Text            = bill.BillingDays.ToString();
                            txtCounterReadingStart.Text    = bill.CounterReadingStart.ToString();
                            txtCounterReadingEnd.Text      = bill.CounterReadingEnd.ToString();
                            txtTotalHCF.Text               = bill.TotalHCF.ToString();
                            txtTotalGallons.Text           = bill.TotalGallons.ToString();
                            txtFirstTierConsumption.Text   = bill.FirstTierConsumption.ToString();
                            txtSecondTierConsumption.Text  = bill.SecondTierConsumption.ToString();
                            txtLastTierConsumption.Text    = bill.LastTierConsumption.ToString();
                            txtWaterCharges.Text           = bill.WaterCharges.ToString();
                            txtSewerCharges.Text           = bill.SewerCharges.ToString();
                            txtEnvironmentCharges.Text     = bill.EnvironmentCharges.ToString();
                            txtServiceCharges.Text         = bill.ServiceCharges.ToString();
                            txtTotalCharges.Text           = bill.TotalCharges.ToString();
                            txtLocalTaxes.Text             = bill.LocalTaxes.ToString();
                            txtStateTaxes.Text             = bill.StateTaxes.ToString();
                            dtpPaymentDueDate.Value        = bill.PaymentDueDate;
                            txtAmountDue.Text              = bill.AmountDue.ToString();
                            dtpLatePaymentDueDate.Value    = bill.LatePaymentDueDate;
                            txtLateAmountDue.Text          = bill.LateAmountDue.ToString();
                        }
                    }
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client       =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text  = client.AccountName;
                                txtAccountType.Text  = client.AccountType;
                                strMeterNumber       = client.MeterNumber;
                                txtAddress.Text      = client.Address;
                                txtCity.Text         = client.City;
                                txtCounty.Text       = client.County;
                                txtState.Text        = client.State;
                                txtZIPCode.Text      = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                string strActual = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strActual))
                {
                    MessageBox.Show("You must type a valid account number of " +
                                    "a customer whose account you want to view.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                List<Customer> clients = new List<Customer>();
                string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers = new FileInfo(strCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == mtbAccountNumber.Text)
                            {
                                txtAccountName.Text = client.AccountName;
                                txtAccountType.Text = client.AccountType;
                                strMeterNumber      = client.MeterNumber;
                                txtAddress.Text     = client.Address;
                                txtCity.Text        = client.City;
                                txtCounty.Text      = client.County;
                                txtState.Text       = client.State;
                                txtZIPCode.Text     = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0d, counterEnd = 0d;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption            = counterEnd - counterStart;
                double gallons                = consumption * 748.05;
                string strAccountType         = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges           = tiers.first + tiers.second + tiers.last;
                double sewerCharges           = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges             = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges             = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges           = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes             = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes             = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue                 = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text              = consumption.ToString();
                txtTotalGallons.Text          = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text  = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text   = tiers.last.ToString("F");
                txtWaterCharges.Text          = waterCharges.ToString("F");
                txtSewerCharges.Text          = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text    = envCharges.ToString("F");
                txtServiceCharges.Text        = srvCharges.ToString("F");
                txtTotalCharges.Text          = totalCharges.ToString("F");
                txtLocalTaxes.Text            = localTaxes.ToString("F");
                txtStateTaxes.Text            = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value       = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text             = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value   = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text         = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
    
            private void btnUpdateWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to update.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strAccountNumber = mtbAccountNumber.Text.Replace(" ", "").Replace("-", "");
    
                if (string.IsNullOrEmpty(strAccountNumber) | string.IsNullOrEmpty(txtAccountName.Text))
                {
                    MessageBox.Show("You must provide an account number of the customer " +
                                    "whose water bill you are trying to update. " +
                                    "After providing the account number, click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills       = string.Empty;
                List<WaterBill> bills      = new List<WaterBill>();
                string fileWaterBills      = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills      = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists    == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        foreach (WaterBill bill in bills)
                        {
                            if (bill.BillNumber            == txtBillNumber.Text)
                            {
                                bill.AccountNumber         =              mtbAccountNumber.Text;
                                bill.MeterReadingStartDate =              dtpMeterReadingStartDate.Value;
                                bill.MeterReadingEndDate   =              dtpMeterReadingEndDate.Value;
                                bill.BillingDays           =    int.Parse(txtBillingDays.Text);
                                bill.CounterReadingStart   =    int.Parse(txtCounterReadingStart.Text);
                                bill.CounterReadingEnd     =    int.Parse(txtCounterReadingEnd.Text);
                                bill.TotalHCF              =    int.Parse(txtTotalHCF.Text);
                                bill.TotalGallons          =    int.Parse(txtTotalGallons.Text);
                                bill.FirstTierConsumption  = double.Parse(txtFirstTierConsumption.Text);
                                bill.SecondTierConsumption = double.Parse(txtSecondTierConsumption.Text);
                                bill.LastTierConsumption   = double.Parse(txtLastTierConsumption.Text);
                                bill.WaterCharges          = double.Parse(txtWaterCharges.Text);
                                bill.SewerCharges          = double.Parse(txtSewerCharges.Text);
                                bill.EnvironmentCharges    = double.Parse(txtEnvironmentCharges.Text);
                                bill.ServiceCharges        = double.Parse(txtServiceCharges.Text);
                                bill.TotalCharges          = double.Parse(txtTotalCharges.Text);
                                bill.LocalTaxes            = double.Parse(txtLocalTaxes.Text);
                                bill.StateTaxes            = double.Parse(txtStateTaxes.Text);
                                bill.PaymentDueDate        =              dtpPaymentDueDate.Value;
                                bill.AmountDue             = double.Parse(txtAmountDue.Text);
                                bill.LatePaymentDueDate    =              dtpLatePaymentDueDate.Value;
                                bill.LateAmountDue         = double.Parse(txtLateAmountDue.Text);
                            }
                        }
                    }
    
                    using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                    {
                        xsWaterBills.Serialize(twWaterBills, bills);
                    }
                }
    
                Close();
            }
    
            private void Editor_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterBillEditorDisplaying == true)
                {
                    WaterDistribution.WaterBillEditorDisplaying = false;
                    Close();
                }
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

23. In the Solution Explorer, double-click WaterDistribution.cs to select the main form of the application
24. On the menu bar of the form, click Water Bills and, below it, double-click Update Water Bill...
25. Implement the event as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            . . .
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                . . .   
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
            private void miViewWaterBills_Click(object sender, EventArgs e)
            {
                if (WaterBillsDisplaying == false)
                {
                    waterBills = new WaterBills.Central();
    
                    waterBills.MdiParent = this;
                    waterBills.Show();
    
                    WaterBillsDisplaying = true;
                }
                else
                {
                    waterBills.BringToFront();
                }
            }
    
            private void miWaterBillsCreate_Click(object sender, EventArgs e)
            {
                if (WaterBillCreateDisplaying == false)
                {
                    waterBillCreate = new WaterBills.Create();
    
                    waterBillCreate.MdiParent = this;
                    waterBillCreate.Show();
    
                    WaterBillCreateDisplaying = true;
                }
                else
                {
                    waterBillCreate.BringToFront();
                }
            }
    
            private void miWaterBillsDetails_Click(object sender, EventArgs e)
            {
                if (WaterBillDetailsDisplaying == false)
                {
                    waterBillDetails = new();
                    waterBillDetails.MdiParent = this;
                    waterBillDetails.Show();
    
                    WaterBillDetailsDisplaying = true;
                }
                else
                {
                    waterBillDetails.BringToFront();
                }
            }
    
            private void miWaterBillsEditor_Click(object sender, EventArgs e)
            {
                if (WaterBillEditorDisplaying == false)
                {
                    waterBillEditor = new();
                    waterBillEditor.MdiParent = this;
                    waterBillEditor.Show();
    
                    WaterBillEditorDisplaying = true;
                }
                else
                {
                    waterBillEditor.BringToFront();
                }
            }
        }
    }

26. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

27. On the main menu of the central form of the application, click Water Meters and click View Water Meters

    

28. On the main menu of the central form of the application, click Water Bills and click Update Water Bill

    

29. In the Water Bill # text, type 923633
30. Click the Find Water Bill button

    

31. Change the following values:

    Account #:                9249-379-6848 and click Find Customer Account
    Meter Reading Start Date: 1/19/2010
    Meter Reading End Date:   4/17/2010
    Counter Reading Start:    256953
    Counter Reading End:      256966

32. Click the Evaluate Water Bill button:

    

33. Click the Update Water Bill button and click OK on the message box:

    

34. Close the forms and return to your programming environment

Deleting a Water Bill

.

Practical Learning: Deleting a Water Bill

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form(Windows Forms)...
2. In the Name text box, replace the string with Delete as the name of the form
3. Press Enter
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   Button		&Find Water Bill	btnFindWaterBill
   GroupBox		Customer Information
   Label		&Account #:
   TextBox			txtAccountNumber	Enabled: False
   Label		Account Name:
   TextBox			txtAccountName	Enabled: False
   Label		Account Type:
   TextBox			txtAccountType	Enabled: False
   Label		Address:		Enabled: False
   TextBox			txtAddress	Enabled: False
   TextBox			txtCity
   TextBox			txtCounty	Enabled: False
   TextBox			txtState	Enabled: False
   TextBox			txtZIPCode	Enabled: False
   Label		________________________________
   Label		Meter Details:
   TextBox			txtMeterDetails	Enabled: False
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Text Box			txtMeterReadingStartDate	Enabled: False
   Label		Meter Reading &End Date:
   Text Box			txtMeterReadingEndDate	Enabled: False
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart	Enabled: False
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd	Enabled: False
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays	Enabled: False
   Label		Total HCF:
   TextBox			txtTotalHCF	Enabled: False
   Label		Total Gallons:
   TextBox			txtTotalGallons	Enabled: False
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption	Enabled: False
   Label		Second Tier:
   TextBox			txtSecondTierConsumption	Enabled: False
   Label		Last Tier:
   TextBox			txtLastTierConsumption	Enabled: False
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges	Enabled: False
   Label		Sewer Charges:
   TextBox			txtSewerCharges	Enabled: False
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges	Enabled: False
   Label		Service Charges:
   TextBox			txtServiceCharges	Enabled: False
   Label		Total Charges:
   TextBox			txtTotalCharges	Enabled: False
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes	Enabled: False
   Label		State Taxes:
   TextBox			txtStateTaxes	Enabled: False
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate	Enabled: False
   Label		Amount Due:
   TextBox			txtAmountDue	Enabled: False
   Label		Late Payment Due Date:
   Text Box			txtLatePaymentDueDate	Enabled: False
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		&Delete Water Bill	btnDeleteWaterBill
   Button		&Close	btnClose

5. On the form, double-click the Find Water Bill button
6. Change the document as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Delete: Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBillAccount_Click(object sender, EventArgs e)
           {
               
           }
       }
   }

7. Return to the form and double-click the Delete Water Bill button
8. Implement the events as follows:

   using System.Xml.Serialization;
   using StellarWaterPoint50.Models;
   
   namespace StellarWaterPoint50.WaterBills
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(txtBillNumber.Text))
               {
                   MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point8\WaterBills.xml";
               XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               string? strAccountNumber = string.Empty;
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
   
                       IEnumerable<WaterBill> invoices = bills.Where(invoice => invoice.BillNumber == txtBillNumber.Text);
   
                       foreach (WaterBill bill in invoices)
                       {
                           txtAccountNumber.Text = bill.AccountNumber;
                           txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                           txtMeterReadingEndDate.Text = bill.MeterReadingEndDate.ToLongDateString();
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           txtPaymentDueDate.Text = bill.PaymentDueDate.ToLongDateString();
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           txtLatePaymentDueDate.Text = bill.LatePaymentDueDate.ToLongDateString();
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                   }
               }
   
               List<Customer> clients = new List<Customer>();
               string strCustomers = @"C:\Stellar Water Point8\Customers.xml";
               XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
   
               FileInfo fiCustomers = new FileInfo(strCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
   
                       clients.ForEach(client =>
                       {
                           if (client.AccountNumber == txtAccountNumber.Text)
                           {
                               txtAccountName.Text = client.AccountName;
                               txtAccountType.Text = client.AccountType;
                               strMeterNumber = client.MeterNumber;
                               txtAddress.Text = client.Address;
                               txtCity.Text = client.City;
                               txtCounty.Text = client.County;
                               txtState.Text = client.State;
                               txtZIPCode.Text = client.ZIPCode;
                           }
                       });
                   }
               }
   
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
               XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
   
               FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
   
                       WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
   
                       if (meter is not null)
                       {
                           txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnDeleteWaterBill_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(txtBillNumber.Text))
               {
                   MessageBox.Show("You must provide a bill number for the water bill you are trying to update.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterBills       = string.Empty;
               List<WaterBill> bills      = new List<WaterBill>();
               string fileWaterBills      = @"C:\Stellar Water Point8\WaterBills.xml";
               XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
   
               FileInfo fiWaterBills      = new FileInfo(fileWaterBills);
   
               if (fiWaterBills.Exists    == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
   
                       foreach (WaterBill bill in bills)
                       {
                           if(bill.BillNumber == txtBillNumber.Text)
                           {
                               if(MessageBox.Show("Are you sure you want to delete (or cancel) this water invoice " +
                                                  "whose bill number is " + txtBillNumber.Text + "?",
                                                  "Stellar Water Point",
                                                  MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
                               {
                                   bills.Remove(bill);
   
                                   MessageBox.Show("The water bill whose bill number is " +
                                                   txtBillNumber.Text + " has been canceled (or deleted from our system).",
                                                   "Stellar Water Point",
                                                   MessageBoxButtons.OK, MessageBoxIcon.Information);
                                   break;
                               }                
                           }
                       }
                   }
   
                   using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                   {
                       xsWaterBills.Serialize(twWaterBills, bills);
                   }
               }
   
               Close();
           }
       }
   }

9. In the Solution Explorer, right-click WaterDistribution.cs and click View Code
10. Change the document as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool WaterMetersDisplaying;
            public static bool WaterMeterCreateDisplaying;
            public static bool WaterMeterDetailsDisplaying;
            public static bool WaterMeterEditorDisplaying;
            public static bool WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central waterMeters;
            private WaterMeters.Create waterMeterCreate;
            private WaterMeters.Details waterMeterDetails;
            private WaterMeters.Editor waterMeterEditor;
            private WaterMeters.Delete waterMeterDelete;
    
            public static bool CustomersDisplaying;
            public static bool CustomerCreateDisplaying;
            public static bool CustomerDetailsDisplaying;
            public static bool CustomerEditorDisplaying;
            public static bool CustomerDeleteDisplaying;
    
            private Customers.Central customers;
            private Customers.Create customerCreate;
            private Customers.Details customerDetails;
            private Customers.Editor customerEditor;
            private Customers.Delete customerDelete;
    
            public static bool WaterBillsDisplaying;
            public static bool WaterBillCreateDisplaying;
            public static bool WaterBillDetailsDisplaying;
            public static bool WaterBillEditorDisplaying;
            public static bool WaterBillDeleteDisplaying;
    
            private WaterBills.Central waterBills;
            private WaterBills.Create waterBillCreate;
            private WaterBills.Details waterBillDetails;
            private WaterBills.Editor waterBillEditor;
            private WaterBills.Delete waterBillDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying = false;
                WaterMeterCreateDisplaying = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying = false;
                WaterMeterDeleteDisplaying = false;
    
                waterMeters = new WaterMeters.Central();
                waterMeterCreate = new WaterMeters.Create();
                waterMeterDetails = new WaterMeters.Details();
                waterMeterEditor = new WaterMeters.Editor();
                waterMeterDelete = new WaterMeters.Delete();
    
                CustomersDisplaying = false;
                CustomerCreateDisplaying = false;
                CustomerDetailsDisplaying = false;
                CustomerEditorDisplaying = false;
                CustomerDeleteDisplaying = false;
    
                customers = new Customers.Central();
                customerCreate = new Customers.Create();
                customerDetails = new Customers.Details();
                customerEditor = new Customers.Editor();
                customerDelete = new Customers.Delete();
    
                WaterBillsDisplaying = false;
                WaterBillCreateDisplaying = false;
                WaterBillDetailsDisplaying = false;
                WaterBillEditorDisplaying = false;
                WaterBillDeleteDisplaying = false;
    
                waterBills = new WaterBills.Central();
                waterBillCreate = new WaterBills.Create();
                waterBillDetails = new WaterBills.Details();
                waterBillEditor = new WaterBills.Editor();
                waterBillDelete = new WaterBills.Delete();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            . . .
    
        }
    }

11. In the Solution Explorer, in the WaterBills folder, double-click Delete
12. Click an unoccupied area of the form to select it
13. In the Solution Explorer, click the Events button
14. In the Events section of the Properties window, double-click FormClosing
15. Return to the form and double-click the Close button
16. Implement the events as follows:

    using System.Xml.Serialization;
    using StellarWaterPoint50.Models;
    
    namespace StellarWaterPoint50.WaterBills
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to creator save.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills       = string.Empty;
                List<WaterBill> bills      = new List<WaterBill>();
                string fileWaterBills      = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                string? strAccountNumber   = string.Empty;
    
                if (fiWaterBills.Exists    == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        IEnumerable<WaterBill> invoices = bills.Where(invoice => invoice.BillNumber == txtBillNumber.Text);
    
                        foreach (WaterBill bill in invoices)
                        {
                            txtAccountNumber.Text         = bill.AccountNumber;
                            txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                            txtMeterReadingEndDate.Text   = bill.MeterReadingEndDate.ToLongDateString();
                            txtBillingDays.Text           = bill.BillingDays.ToString();
                            txtCounterReadingStart.Text   = bill.CounterReadingStart.ToString();
                            txtCounterReadingEnd.Text     = bill.CounterReadingEnd.ToString();
                            txtTotalHCF.Text              = bill.TotalHCF.ToString();
                            txtTotalGallons.Text          = bill.TotalGallons.ToString();
                            txtFirstTierConsumption.Text  = bill.FirstTierConsumption.ToString();
                            txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                            txtLastTierConsumption.Text   = bill.LastTierConsumption.ToString();
                            txtWaterCharges.Text          = bill.WaterCharges.ToString();
                            txtSewerCharges.Text          = bill.SewerCharges.ToString();
                            txtEnvironmentCharges.Text    = bill.EnvironmentCharges.ToString();
                            txtServiceCharges.Text        = bill.ServiceCharges.ToString();
                            txtTotalCharges.Text          = bill.TotalCharges.ToString();
                            txtLocalTaxes.Text            = bill.LocalTaxes.ToString();
                            txtStateTaxes.Text            = bill.StateTaxes.ToString();
                            txtPaymentDueDate.Text        = bill.PaymentDueDate.ToLongDateString();
                            txtAmountDue.Text             = bill.AmountDue.ToString();
                            txtLatePaymentDueDate.Text    = bill.LatePaymentDueDate.ToLongDateString();
                            txtLateAmountDue.Text         = bill.LateAmountDue.ToString();
                        }
                    }
                }
    
                List<Customer> clients    = new List<Customer>();
                string strCustomers       = @"C:\Stellar Water Point8\Customers.xml";
                XmlSerializer xsCustomers = new XmlSerializer(typeof(List<Customer>));
    
                FileInfo fiCustomers      = new FileInfo(strCustomers);
    
                string? strMeterNumber    = string.Empty;
    
                if (fiCustomers.Exists    == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        clients = (List<Customer>)xsCustomers.Deserialize(trCustomers)!;
    
                        clients.ForEach(client =>
                        {
                            if (client.AccountNumber == txtAccountNumber.Text)
                            {
                                txtAccountName.Text  = client.AccountName;
                                txtAccountType.Text  = client.AccountType;
                                strMeterNumber       = client.MeterNumber;
                                txtAddress.Text      = client.Address;
                                txtCity.Text         = client.City;
                                txtCounty.Text       = client.County;
                                txtState.Text        = client.State;
                                txtZIPCode.Text      = client.ZIPCode;
                            }
                        });
                    }
                }
    
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string strWaterMeters = @"C:\Stellar Water Point8\WaterMeters.xml";
                XmlSerializer xsWaterMeters = new XmlSerializer(typeof(List<WaterMeter>));
    
                FileInfo fiWaterMeters = new FileInfo(strWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        waterMeters = (List<WaterMeter>)xsWaterMeters.Deserialize(trWaterMeters)!;
    
                        WaterMeter? meter = waterMeters.Find(m => m.MeterNumber == strMeterNumber)!;
    
                        if (meter is not null)
                        {
                            txtMeterDetails.Text = meter.Make + " " + meter.Model + " (Mtr Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnDeleteWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must provide a bill number for the water bill you are trying to update.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills       = string.Empty;
                List<WaterBill> bills      = new List<WaterBill>();
                string fileWaterBills      = @"C:\Stellar Water Point8\WaterBills.xml";
                XmlSerializer xsWaterBills = new XmlSerializer(typeof(List<WaterBill>));
    
                FileInfo fiWaterBills      = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists    == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        bills = (List<WaterBill>)xsWaterBills.Deserialize(trWaterBills)!;
    
                        foreach (WaterBill bill in bills)
                        {
                            if(bill.BillNumber == txtBillNumber.Text)
                            {
                                if(MessageBox.Show("Are you sure you want to delete (or cancel) this water invoice " +
                                                   "whose bill number is " + txtBillNumber.Text + "?",
                                                   "Stellar Water Point",
                                                   MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
                                {
                                    bills.Remove(bill);
    
                                    MessageBox.Show("The water bill whose bill number is " +
                                                    txtBillNumber.Text + " has been canceled (or deleted from our system).",
                                                    "Stellar Water Point",
                                                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                                    break;
                                }                
                            }
                        }
                    }
    
                    using (TextWriter twWaterBills = new StreamWriter(fiWaterBills.FullName))
                    {
                        xsWaterBills.Serialize(twWaterBills, bills);
                    }
                }
    
                Close();
            }
    
            private void Delete_FormClosing(object sender, FormClosingEventArgs e)
            {
                if (WaterDistribution.WaterBillDeleteDisplaying == true)
                {
                    WaterDistribution.WaterBillDeleteDisplaying = false;
                    Close();
                }
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

17. In the Solution Explorer, double-click WaterDistribution.cs to display the central form of the application
18. On the menu bar of the form, click Water Bills and, below it, double-click Delete Water Bill...
19. Return to the form
20. On the menu bar of the form, click Help and, below it, About Stellar Water Point
21. Return to the form
22. On the menu bar of the form, click File and, below it, double-click Exit
23. Implement the events as follows:

    namespace StellarWaterPoint50
    {
        public partial class WaterDistribution : Form
        {
            public static bool              WaterMetersDisplaying;
            public static bool              WaterMeterCreateDisplaying;
            public static bool              WaterMeterDetailsDisplaying;
            public static bool              WaterMeterEditorDisplaying;
            public static bool              WaterMeterDeleteDisplaying;
    
            private WaterMeters.Central     waterMeters;
            private WaterMeters.Create      waterMeterCreate;
            private WaterMeters.Details     waterMeterDetails;
            private WaterMeters.Editor      waterMeterEditor;
            private WaterMeters.Delete      waterMeterDelete;
    
            public static bool              CustomersDisplaying;
            public static bool              CustomerCreateDisplaying;
            public static bool              CustomerDetailsDisplaying;
            public static bool              CustomerEditorDisplaying;
            public static bool              CustomerDeleteDisplaying;
    
            private Customers.Central       customers;
            private Customers.Create        customerCreate;
            private Customers.Details       customerDetails;
            private Customers.Editor        customerEditor;
            private Customers.Delete        customerDelete;
    
            public static bool              WaterBillsDisplaying;
            public static bool              WaterBillCreateDisplaying;
            public static bool              WaterBillDetailsDisplaying;
            public static bool              WaterBillEditorDisplaying;
            public static bool              WaterBillDeleteDisplaying;
    
            private WaterBills.Central      waterBills;
            private WaterBills.Create       waterBillCreate;
            private WaterBills.Details      waterBillDetails;
            private WaterBills.Editor       waterBillEditor;
            private WaterBills.Delete       waterBillDelete;
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                WaterMetersDisplaying       = false;
                WaterMeterCreateDisplaying  = false;
                WaterMeterDetailsDisplaying = false;
                WaterMeterEditorDisplaying  = false;
                WaterMeterDeleteDisplaying  = false;
    
                waterMeters                 = new WaterMeters.Central();
                waterMeterCreate            = new WaterMeters.Create();
                waterMeterDetails           = new WaterMeters.Details();
                waterMeterEditor            = new WaterMeters.Editor();
                waterMeterDelete            = new WaterMeters.Delete();
    
                CustomersDisplaying         = false;
                CustomerCreateDisplaying    = false;
                CustomerDetailsDisplaying   = false;
                CustomerEditorDisplaying    = false;
                CustomerDeleteDisplaying    = false;
    
                customers                   = new Customers.Central();
                customerCreate              = new Customers.Create();
                customerDetails             = new Customers.Details();
                customerEditor              = new Customers.Editor();
                customerDelete              = new Customers.Delete();
    
                WaterBillsDisplaying        = false;
                WaterBillCreateDisplaying   = false;
                WaterBillDetailsDisplaying  = false;
                WaterBillEditorDisplaying   = false;
                WaterBillDeleteDisplaying   = false;
    
                waterBills                  = new WaterBills.Central();
                waterBillCreate             = new WaterBills.Create();
                waterBillDetails            = new WaterBills.Details();
                waterBillEditor             = new WaterBills.Editor();
                waterBillDelete             = new WaterBills.Delete();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point8");
            }
    
            private void miWindowArrange_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.ArrangeIcons);
            }
    
            private void miWindowCascade_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.Cascade);
            }
    
            private void miWindowTileHorizontal_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileHorizontal);
            }
    
            private void miWindowTileVertical_Click(object sender, EventArgs e)
            {
                LayoutMdi(MdiLayout.TileVertical);
            }
    
            private void miWaterMetersView_Click(object sender, EventArgs e)
            {
                if (WaterMetersDisplaying == false)
                {
                    waterMeters = new WaterMeters.Central();
    
                    waterMeters.MdiParent = this;
                    waterMeters.Show();
    
                    WaterMetersDisplaying = true;
                }
                else
                {
                    waterMeters.BringToFront();
                }
            }
    
            private void miWaterMetersCreate_Click(object sender, EventArgs e)
            {
                if (WaterMeterCreateDisplaying == false)
                {
                    waterMeterCreate = new();
                    waterMeterCreate.MdiParent = this;
                    waterMeterCreate.Show();
    
                    WaterMeterCreateDisplaying = true;
                }
                else
                {
                    waterMeterCreate.BringToFront();
                }
            }
    
            private void miWaterMetersDetails_Click(object sender, EventArgs e)
            {
                if (WaterMeterDetailsDisplaying == false)
                {
                    waterMeterDetails = new();
                    waterMeterDetails.MdiParent = this;
                    waterMeterDetails.Show();
    
                    WaterMeterDetailsDisplaying = true;
                }
                else
                {
                    waterMeterDetails.BringToFront();
                }
            }
    
            private void miWaterMetersEditor_Click(object sender, EventArgs e)
            {
                if (WaterMeterEditorDisplaying == false)
                {
                    waterMeterEditor = new();
                    waterMeterEditor.MdiParent = this;
                    waterMeterEditor.Show();
    
                    WaterMeterEditorDisplaying = true;
                }
                else
                {
                    waterMeterEditor.BringToFront();
                }
            }
    
            private void miWaterMetersDelete_Click(object sender, EventArgs e)
            {
                if (WaterMeterDeleteDisplaying == false)
                {
                    waterMeterDelete = new();
                    waterMeterDelete.MdiParent = this;
                    waterMeterDelete.Show();
    
                    WaterMeterDeleteDisplaying = true;
                }
                else
                {
                    waterMeterDelete.BringToFront();
                }
            }
    
            private void miViewCustomers_Click(object sender, EventArgs e)
            {
                if (CustomersDisplaying == false)
                {
                    customers = new Customers.Central();
    
                    customers.MdiParent = this;
                    customers.Show();
    
                    CustomersDisplaying = true;
                }
                else
                {
                    customers.BringToFront();
                }
            }
    
            private void miCustomersCreate_Click(object sender, EventArgs e)
            {
                if (CustomerCreateDisplaying == false)
                {
                    customerCreate = new();
                    customerCreate.MdiParent = this;
                    customerCreate.Show();
    
                    CustomerCreateDisplaying = true;
                }
                else
                {
                    customerCreate.BringToFront();
                }
            }
    
            private void miCustomersDetails_Click(object sender, EventArgs e)
            {
                if (CustomerDetailsDisplaying == false)
                {
                    customerDetails = new();
                    customerDetails.MdiParent = this;
                    customerDetails.Show();
    
                    CustomerDetailsDisplaying = true;
                }
                else
                {
                    customerDetails.BringToFront();
                }
            }
    
            private void miCustomersEditor_Click(object sender, EventArgs e)
            {
                if (CustomerEditorDisplaying == false)
                {
                    customerEditor = new();
                    customerEditor.MdiParent = this;
                    customerEditor.Show();
    
                    CustomerEditorDisplaying = true;
                }
                else
                {
                    customerEditor.BringToFront();
                }
            }
    
            private void miCustomersDelete_Click(object sender, EventArgs e)
            {
                if (CustomerDeleteDisplaying == false)
                {
                    customerDelete = new();
                    customerDelete.MdiParent = this;
                    customerDelete.Show();
    
                    CustomerDeleteDisplaying = true;
                }
                else
                {
                    customerDelete.BringToFront();
                }
            }
    
            private void miViewWaterBills_Click(object sender, EventArgs e)
            {
                if (WaterBillsDisplaying == false)
                {
                    waterBills = new WaterBills.Central();
    
                    waterBills.MdiParent = this;
                    waterBills.Show();
    
                    WaterBillsDisplaying = true;
                }
                else
                {
                    waterBills.BringToFront();
                }
            }
    
            private void miWaterBillsCreate_Click(object sender, EventArgs e)
            {
                if (WaterBillCreateDisplaying == false)
                {
                    waterBillCreate = new WaterBills.Create();
    
                    waterBillCreate.MdiParent = this;
                    waterBillCreate.Show();
    
                    WaterBillCreateDisplaying = true;
                }
                else
                {
                    waterBillCreate.BringToFront();
                }
            }
    
            private void miWaterBillsDetails_Click(object sender, EventArgs e)
            {
                if (WaterBillDetailsDisplaying == false)
                {
                    waterBillDetails = new();
                    waterBillDetails.MdiParent = this;
                    waterBillDetails.Show();
    
                    WaterBillDetailsDisplaying = true;
                }
                else
                {
                    waterBillDetails.BringToFront();
                }
            }
    
            private void miWaterBillsEditor_Click(object sender, EventArgs e)
            {
                if (WaterBillEditorDisplaying == false)
                {
                    waterBillEditor = new();
                    waterBillEditor.MdiParent = this;
                    waterBillEditor.Show();
    
                    WaterBillEditorDisplaying = true;
                }
                else
                {
                    waterBillEditor.BringToFront();
                }
            }
    
            private void miWaterBillsDeletion_Click(object sender, EventArgs e)
            {
                if (WaterBillDeleteDisplaying == false)
                {
                    waterBillDelete = new();
                    waterBillDelete.MdiParent = this;
                    waterBillDelete.Show();
    
                    WaterBillDeleteDisplaying = true;
                }
                else
                {
                    waterBillDelete.BringToFront();
                }
            }
    
            private void miHelpAbout_Click(object sender, EventArgs e)
            {
                AboutSWP about = new();
    
                about.ShowDialog();
            }
    
            private void miFileExit_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

24. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

25. On the main menu of the central form of the application, click Water Bills and click View Water Bills

    

26. On the main menu of the central form of the application, click Water Bills and click Delete Water Bill

    

27. In the Water Bill # text box, type 917829
28. Click Find Water Bill

    

29. Click Delete Water Bill
30. Read the message in the message box and click Yes:

    

31. Close the forms and return to your programming environment
32. Close your programming environment

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