Application Setup

Introduction

In this exercise, we will create a semi-small graphical application for a water distribution company that provides water for various types of customers, including residential families, private businesses, government buildings, etc. The application uses a text-based database that processes records using collection classes. The records are saved in JSON files.

Practical Learning: Introducing the Application

1. Start Microsoft Visual Studio
2. In the Visual Studio 2026 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 StellarWaterPoint2
7. Click Next
8. In the Framework combo box, select the highest version: .NET 10.0 (Long Term Support)
9. Click Create
10. To create a folder, in the Solution Explorer -> Add -> Folder
11. Type Models as the name of the folder
12. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
13. Type MsgBox as the name of the file and class
14. Click Add
15. Change the class as follows:

    namespace StellarWaterPoint2.Models
    {
        public enum Answer { No = 0, Yes = 1, Cancel = 2, Unknown = 3 }
    
        internal static class MsgBox
        {
            public static void Show(string message)
            {
                MessageBox.Show(message,
                                "Stellar Water Point",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Information);
            }
    
            public static Answer Question(string message)
            {
                DialogResult result = MessageBox.Show(message,
                                                      "Stellar Water Point",
                                                      MessageBoxButtons.YesNoCancel,
                                                      MessageBoxIcon.Question);
    
                switch (result)
                {
                    case DialogResult.Yes:
                        return Answer.Yes;
                    case DialogResult.No:
                        return Answer.No;
                    case DialogResult.Cancel:
                        return Answer.Cancel;
                    default:
                        return Answer.Unknown;
                }
            }
        }
    }

16. In the Solution Explorer, right-click Models -> Add -> Class
17. Set the file Name to Repository
18. Click Add

The Main Form of the Application

Our application will use a central form acting as a switchboard from which other section-based forms can be accessed.

Practical Learning: Preparing the Main Form of the Application

1. In the Solution Explorer, right-click Form1.cs and click Rename
2. Type WaterDistribution (to get WaterDistribution.cs) and press Enter
3. Read the message on the message box and click Yes
4. Click the body of the form to make sure it is selected.
   In the Properties window, change the following characteristics:
   Text: Stellar Water Point
   StartPosition: CenterScreen
   MaximizeBox: False
5. Double-click an unoccupied area of the form to generate its Load event
6. Implement the event as follows:

   namespace StellarWaterPoint2
   {
       public partial class WaterDistribution : Form
       {
           public WaterDistribution()
           {
               InitializeComponent();
           }
   
           private void WaterDistribution_Load(object sender, EventArgs e)
           {
               Directory.CreateDirectory(@"C:\Stellar Water Point2");
           }
       }
   }

Water Meters

Introduction

The company of our application uses water meters to monitor the amount of water its customers consume. To start, the application needs a list of water meters that are available.

Practical Learning: Displaying Water Meters

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 StellarWaterPoint2.Models
   {
       internal record WaterMeter
       {
           public int     WaterMeterId { get; set; }
           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	Water Meter Id	150
   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. Doubte-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter wm in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(wm.WaterMeterId.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_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add a button to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnWaterMeters	&Water Meters...	Times New Roman, 24pt, style=Bold

14. Double-click the &Water Meters button
15. Impliment the event as follows:

    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.Show();
            }
        }
    }

A Water Meter Record

A water meter must be installed in the location where water is consumed. We will create a form that allows a user to create a new record for a water meter.

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. Type Create
3. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000 Modifiers: Public
   Label			&Water Meter Id:
   TextBox		txtWaterMeterId		Modifiers: Public
   Label			M&ake:
   TextBox		txtMake		Modifiers: Public
   Label			M&odel:
   TextBox		txtModel		Modifiers: Public
   Label			Me&ter Size:
   TextBox		txtMeterSize		Modifiers: Public
   Button		btnOK	&OK	DialogResult: OK
   Button		btnCancel	&Cancel	DialogResult: Cancel

4. Using the Properties window, change some characteristics of the form as follows:

   FormBorderStyle: FixedDialog
   Text:            Stellar Water Point - Create Water Meter
   StartPosition:   CenterScreen
   AcceptButton:    btnOK
   CancelButton:    btnCancel

5. Double-click an unoccupied area of the form to generate its Load event
6. Implement the event as follows:

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterMeters
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void Create_Load(object sender, EventArgs e)
           {
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
       
               int waterMeterId = 0;
               
               if (fiWaterMeters.Exists == true)
               {
   
                   using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       foreach (WaterMeter wm in waterMeters)
                       {
                           waterMeterId = wm.WaterMeterId;
                       }
                   }
               }
               
               txtWaterMeterId.Text = (waterMeterId + 1).ToString();
           }
       }
   }

7. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
8. From the Toolbox, add a button to the form below the list view
9. Change the characteristics of the button as follows:

   

   Control		(Name)	Text
   ListView		No Change	No Change
   Button		btnNewWaterMeter	&New Water Meter...

10. On the Central form, double-click the New Water Meter button
11. Implement the event as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void btnNewWaterMeter_Click(object sender, EventArgs e)
            {
                            Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if(create.mtbMeterNumber.Text.Replace("-", "").Trim() == "")
                    {
                        MsgBox.Show("You must type a meter number. " +
                                    "Otherwise, the water meter cannot be set up.");
                        return;
                    }
    
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
                    }
    
                    WaterMeter wm = new WaterMeter()
                    {
                        WaterMeterId = create.txtWaterMeterId.Text == "" ? 1 : int.Parse(create.txtWaterMeterId.Text),
                        MeterNumber = create.mtbMeterNumber.Text,
                        Make = create.txtMake.Text,
                        Model = create.txtModel.Text,
                        MeterSize = create.txtMeterSize.Text
                    };
    
                    waterMeters.Add(wm);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                    File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
                }
    
                ShowWaterMeters();
            }
        }
    }

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

    

13. On the Central form, click the Water Meters button:

    

14. Click the New Water Meter button:

    

15. 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

    

16. Close the forms and return to your programming environment
17. In the Solution Explorer, double-click WaterDistribution.cs to access the primary form of the application
18. Double-click an unoccupied area of the form to access its code
19. Comment the call of the AccountType class as follows:

    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");            
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

Water Meter Details

When the records of water meters have been created, sometimes, a user may want to view some details about a water meter. We are going to create such a form.

Practical Learning: Creating a Water Meter Record

1. To create a form, in the Solution Explorer, right-click WaterMeters -> 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
   Label			Water Meter Id:
   TextBox		txtWaterMeterId		False	Public
   Button		btnClose	&Close

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterMeters
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MsgBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   foreach (WaterMeter meter in waterMeters)
                   {
                       if (meter.MeterNumber == mtbMeterNumber.Text)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
           }
       }
   }

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

   private void btnClose_Click(object sender, EventArgs e)
   {
       Close();
   }

9. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs to open its form
10. From the Toolbox, add a button to the form below the list view and to the right of the New Water Meter button
11. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		No Change	No Change
    Button		No Change	No Change
    Button		btnViewWaterMeter	&View Water Meter...

12. Double-click the View Water Meter button
13. Change the document as follows:

    private void btnViewWaterMeter_Click(object sender, EventArgs e)
    {
        Details view = new();
                
        view.ShowDialog();
    }

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

    

15. On the Water Distribution form, click the Water Meters button
16. On the Central form of water meters, click the View Water Meter button:

    

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

    

19. Close the forms and return to your programming environment

Updating a Water Meter Details

One of the routine operations performed on a database is to change the details of a record. To support this operation for a water meter, we will create a form that can be used to update the information of a water meter.

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		btnUpdateWaterMeter	&Update Water Meter
   Button		btnClose	&Close

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterMeters
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterMeter_Click(object sender, EventArgs e)
           {
               if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
               {
                   MsgBox.Show("Please provide a meter number, " +
                               "and then click the Find Water Meter button.");
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   foreach (WaterMeter meter in waterMeters)
                   {
                       if (meter.MeterNumber == mtbMeterNumber.Text)
                       {
                           txtWaterMeterId.Text = meter.WaterMeterId.ToString();
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
           }
       }
   }

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

   private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
   {
       if (string.IsNullOrEmpty(mtbMeterNumber.Text))
       {
           MsgBox.Show("You must type a valid meter number, " +
                       "and then click the Find Water Meter button.");
           return;
       }
   
       string strWaterMeters = string.Empty;
       List<WaterMeter> waterMeters = new List<WaterMeter>();
       string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
       FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
       if (fiWaterMeters.Exists == true)
       {
           strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
           waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
           WaterMeter? meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text);
   
           if (meter is not null)
           {
               meter.WaterMeterId = int.Parse(txtWaterMeterId.Text);
               meter.Make = txtMake.Text;
               meter.Model = txtModel.Text;
               meter.MeterSize = txtMeterSize.Text;
   
               JsonSerializerOptions options = new JsonSerializerOptions();
               options.WriteIndented = true;
   
               string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
               File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
           }
       }
   
       Close();
   }

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

    private void btnClose_Click(object sender, EventArgs e)
    {
        Close();
    }

11. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
12. From the Toolbox, add a button to the form below the list view and on the right side of the View Water Meter button
13. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		No Change	No Change
    Button		No Change	No Change
    Button		No Change	No Change
    Button		btnEditWaterMeter	&Edit Water Meter...

14. Display the Central form of the WaterMeters folder
15. Double-click the Update Water Meter button
16. Change the document as follows:

    private void btnEditWaterMeter_Click(object sender, EventArgs e)
    {
        Editor editor = new();
    
        editor.ShowDialog();
    
        ShowWaterMeters();
    }

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

    

18. On the Central form, click the Water Meters button:

    

19. Click the Update Water Meter button:

    

20. In the Meter # text, type 938-705-869
21. Click the Find button

    

22. Change the values as follows:

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

    

23. Click the Update button:

    

24. Close the forms and return to your programming environment

Removing a Water Meter from the Database

If a record of a water meter is not necessary anymore, a user can be asked to delete such a record. We are going to create a form for such an operation.

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
   Label			Make:
   TextBox		txtMake		False
   Label			Model:
   TextBox		txtModel		False
   Label			Meter Size:
   TextBox		txtMeterSize		False
   Button		btnClose	&Close

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterMeters
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterMeter_Click(object sender, EventArgs e)
           {
               if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
               {
                   MsgBox.Show("Please provide a meter number, " +
                               "and then click the Find Water Meter button.");
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   foreach (WaterMeter meter in waterMeters)
                   {
                       if (meter.MeterNumber == mtbMeterNumber.Text)
                       {
                           txtWaterMeterId.Text = meter.WaterMeterId.ToString();
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Delete Water Meter button
8. Change the document as tollows:

   private void btnDeleteWaterMeter_Click(object sender, EventArgs e)
   {
       if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
       {
           MsgBox.Show("You must type a valid meter number, " +
                       "and then click the Find Water Meter button.");
           return;
       }
   
       string strWaterMeters = string.Empty;
       List<WaterMeter> waterMeters = new List<WaterMeter>();
       string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
       FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
       if (fiWaterMeters.Exists == true)
       {
           strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
           waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
           WaterMeter meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text)!;
   
           if (meter is not null)
           {
               if (MsgBox.Question("Are you sure you want to delete this water meter " +
                                   "(you cannot undo the action)?") == Answer.Yes)
               {
                   waterMeters.Remove(meter);
   
                   JsonSerializerOptions options = new JsonSerializerOptions();
                   options.WriteIndented = true;
   
                   string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                   File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
   
                   MsgBox.Show("The water meter has been removed from our database.");
               }
           }
       }
   
       Close();
   }

9. Return to the form and double-click the Close button
10. Change the document as tollows:

    private void btnClose_Click(object sender, EventArgs e)
    {
        Close();
    }

11. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
12. From the Toolbox, add two buttons to the form below the list view and on the right side of the Edit Water Meter button
13. Change the characteristics of the buttons as follows:

    

    Control		(Name)	Text	Anchor
    ListView		lvwWaterMeters		Top, Bottom, Left, Right
    Button		btnNewWaterMeter	&New Water Meter...	Bottom, Right
    Button		btnViewWaterMeter	&View Water Meter...	Bottom, Right
    Button		btnEditWaterMeter	&Edit Water Meter...	Bottom, Right
    Button		btnDeleteWateMeter	&Delete Water Meter...	Bottom, Right
    Button		btnClose	&Close	Bottom, Right

14. On the form, double-click the Delete Water Meter button
15. Return to the Central form of the water meters and double-click the Close button
16. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter wm in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(wm.WaterMeterId.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_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void btnNewWaterMeter_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if (create.mtbMeterNumber.Text.Replace("-", "").Trim() == "")
                    {
                        MsgBox.Show("You must type a meter number. " +
                                    "Otherwise, the water meter cannot be set up.");
                        return;
                    }
    
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
                    }
    
                    WaterMeter wm = new WaterMeter()
                    {
                        WaterMeterId = create.txtWaterMeterId.Text == "" ? 1 : int.Parse(create.txtWaterMeterId.Text),
                        MeterNumber = create.mtbMeterNumber.Text,
                        Make = create.txtMake.Text,
                        Model = create.txtModel.Text,
                        MeterSize = create.txtMeterSize.Text
                    };
    
                    waterMeters.Add(wm);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                    File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
                }
    
                ShowWaterMeters();
            }
    
            private void btnViewWaterMeter_Click(object sender, EventArgs e)
            {
                Details view = new();
    
                view.Show();
            }
    
            private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnDeleteWaterMeter_Click(object sender, EventArgs e)
            {
                Delete delete = new Delete();
    
                delete.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

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

    

18. On the Central form, click the Water Meters button:

    

19. On the Central form of the water meters, click the Delete Water Meter button:

    

20. In the Meter # text, type 588-279-663
21. Click the Find button:

    

22. Click the Delete button:

    

23. Read the text on the message box and click Yes
24. Read the other message box and click OK
25. In the same way, delete the other two records
26. Close the forms and return to your programming environment
27. In the Solution Explorer, double-click WaterDistribution.cs
28. Change the document as follows:

    using StellarWaterPoint2.Models;
    using System.Reflection.Metadata;
    using System.Text.Json;
    
    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            private void CreateWaterMeters()
            {
                List<WaterMeter> waterMeters = new List<WaterMeter>();
    
                waterMeters!.Add(new WaterMeter() { WaterMeterId =  1, MeterNumber = "392-494-572", Make = "Constance Technologies", Model = "TG-4822",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  2, MeterNumber = "938-725-869", Make = "Stanford Trend",         Model = "266G",     MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  3, MeterNumber = "588-279-663", Make = "Estellano",              Model = "NCF-226",  MeterSize = "4 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  4, MeterNumber = "186-962-805", Make = "Lansome",                Model = "2800",     MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  5, MeterNumber = "379-386-979", Make = "Planetra",               Model = "P-2020",   MeterSize = "4 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  6, MeterNumber = "580-742-825", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  7, MeterNumber = "849-351-444", Make = "Raynes Energica",        Model = "a1088",    MeterSize = "2 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  8, MeterNumber = "208-428-308", Make = "Constance Technologies", Model = "808D",     MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId =  9, MeterNumber = "738-588-249", Make = "Warrington",             Model = "W4242",    MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 10, MeterNumber = "496-813-794", Make = "Estellano",              Model = "NCF-226",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 11, MeterNumber = "862-715-006", Make = "Warrington",             Model = "W-4040",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 12, MeterNumber = "649-358-184", Make = "Raynes Energica",        Model = "b1700",    MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 13, MeterNumber = "928-317-924", Make = "Gongola",                Model = "GN1000",   MeterSize = "2 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 14, MeterNumber = "595-753-147", Make = "Grass Grill",            Model = "CRC-1000", MeterSize = "1 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 15, MeterNumber = "799-528-461", Make = "Kensa Sons",             Model = "K-584-L",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 16, MeterNumber = "386-468-057", Make = "Estellano",              Model = "NCF-226",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 17, MeterNumber = "938-275-294", Make = "Constance Technologies", Model = "TT-8822",  MeterSize = "4 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 18, MeterNumber = "288-427-585", Make = "Planetra",               Model = "P-2020",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 19, MeterNumber = "394-835-297", Make = "Raynes Energica",        Model = "i2022",    MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 20, MeterNumber = "847-252-246", Make = "Master Stream",          Model = "2000-MS",  MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 21, MeterNumber = "349-725-848", Make = "Planetra",               Model = "P-8000",   MeterSize = "4 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 22, MeterNumber = "713-942-058", Make = "Master Stream",          Model = "3366-MS",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 23, MeterNumber = "747-581-379", Make = "Warrington",             Model = "W4242",    MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 24, MeterNumber = "582-755-263", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 25, MeterNumber = "827-260-758", Make = "Raynes Energica",        Model = "a1088",    MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 26, MeterNumber = "837-806-836", Make = "Lansome",                Model = "7400",     MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 27, MeterNumber = "207-964-835", Make = "Constance Technologies", Model = "TG-6220",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 28, MeterNumber = "296-837-495", Make = "Raynes Energica",        Model = "QG505",    MeterSize = "4 Inches"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 29, MeterNumber = "468-359-486", Make = "Grass Grill",            Model = "KLP-8822", MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 30, MeterNumber = "931-486-003", Make = "Planetra",               Model = "P-2020",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 31, MeterNumber = "483-770-648", Make = "Warren",                 Model = "WWW",      MeterSize = "0.1 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 32, MeterNumber = "592-824-957", Make = "Kensa Sons",             Model = "D-497-H",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 33, MeterNumber = "293-835-704", Make = "Gongola",                Model = "GOL1000",  MeterSize = "1/2 Inch"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 34, MeterNumber = "739-777-749", Make = "Warrington",             Model = "W2200W",   MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 35, MeterNumber = "374-886-284", Make = "Raynes Energica",        Model = "i2022",    MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 36, MeterNumber = "186-959-757", Make = "Kensa Sons",             Model = "M-686-G",  MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 37, MeterNumber = "594-827-359", Make = "Planetra",               Model = "P-8000",   MeterSize = "1 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 38, MeterNumber = "394-739-242", Make = "Master Stream",          Model = "9393-TT",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 39, MeterNumber = "529-283-752", Make = "Constance Technologies", Model = "404T",     MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 40, MeterNumber = "295-770-695", Make = "Warrington",             Model = "W-2286",   MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 41, MeterNumber = "739-749-737", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 42, MeterNumber = "947-528-317", Make = "Gondola",                Model = "GDL-5000", MeterSize = "1 Inch"       });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 43, MeterNumber = "630-207-055", Make = "Lansome",                Model = "2800",     MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 44, MeterNumber = "827-508-248", Make = "Standard Trend",         Model = "428T",     MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 45, MeterNumber = "293-924-869", Make = "Grass Grill",            Model = "CRC-2020", MeterSize = "1/2 Inch"     });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 46, MeterNumber = "928-247-580", Make = "Gondola",                Model = "GOL2000",  MeterSize = "0.34 Inch"    });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 47, MeterNumber = "682-537-380", Make = "Planetra",               Model = "P-2020",   MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 48, MeterNumber = "470-628-850", Make = "Estellano",              Model = "WRT-482",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 49, MeterNumber = "649-373-505", Make = "Constance Technologies", Model = "BD-7000",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new WaterMeter()  { WaterMeterId = 50, MeterNumber = "306-842-497", Make = "Lansome",                Model = "9000",     MeterSize = "3/4 Inches"   });
    
                string strWaterMeters = string.Empty;
                string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
                string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
            }
    
            private void CreateAccountsTypes()
            {
                List<AccountType> types = new List<AccountType>()
                {
                    new AccountType() { AccountTypeId = 1, TypeCode = "OTH", TypeDecription = "Other" },
                    new AccountType() { AccountTypeId = 3, TypeCode = "RES", TypeDecription = "Residential Household" },
                    new AccountType() { AccountTypeId = 2, TypeCode = "BUS", TypeDecription = "General Business, Commercial, Industrial" },
                    new AccountType() { AccountTypeId = 5, TypeCode = "UUO", TypeDecription = "Unidentified or Unclassified Type of Organization" },
                    new AccountType() { AccountTypeId = 4, TypeCode = "SGO", TypeDecription = "Social/Government/Non-Profit Organization, Institutional" },
                    new AccountType() { AccountTypeId = 6, TypeCode = "WAT", TypeDecription = "Water Intensive Business (Agricultural, Laudromat, Hair Salon, Restaurant, etc" }
                };
    
                string strAccountsTypes       = string.Empty;
                string fileAccountsTypes      = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented         = true;
    
                FileInfo fiAccountsTypes      = new FileInfo(fileAccountsTypes);
                string jsAccountsTypes        = JsonSerializer.Serialize(types, typeof(List<AccountType>), options);
                File.WriteAllText(fiAccountsTypes.FullName, jsAccountsTypes);
            }
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                CreateWaterMeters();
                CreateAccountsTypes();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.Show();
            }
        }
    }

29. To execute the application, on the main menu, click Debug -> Start Without Debugging
30. Close the forms and return to your programming environment
31. Change theWaterDistribution.cs document as follows:

    using StellarWaterPoint2.Models;
    using System.Reflection.Metadata;
    using System.Text.Json;
    
    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            private void CreateWaterMeters()
            {
                . . .
            }
    
            private void CreateAccountsTypes()
            {
                . . .
            }
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                // CreateWaterMeters();
                // CreateAccountsTypes();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.Show();
            }
        }
    }

Customers

Introduction

For a water distribution company, a customer is a person, a business, or any entity that consumes water. At a minimum, a computer must keep a list of entities that use its business.

Practical Learning: Introducing Customers

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 AccountType
4. Click Add
5. Change the code as follows:

   namespace StellarWaterPoint2.Models
   {
       internal readonly record struct AccountType
       {
           public readonly int     AccountTypeId  { get; init; }
           public readonly string? TypeCode       { get; init; }
           public readonly string? TypeDecription { get; init; }
       }
   }

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

    namespace StellarWaterPoint2.Models
    {
        public class Customer
        {
            public int     CustomerId    { get; set; }
            public string? AccountNumber { get; set; }
            public string? AccountName   { get; set; }
            public string? MeterNumber   { get; set; }
            public string? AccountType   { 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; }
        }
    }

11. To create a folder, in the Solution Explorer, right-click the StellarWaterPoint2 project -> Add -> New Folder
12. Type Customers as the name of the folder

Displaying Customers

In a later section, we will learn how to create a customer record. When those records exist, a user can display them. We are going to make it possible through a form equipped with a list view

Practical Learning: Displaying Customers

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
   colMeterNumber	Meter #	Center	100
   colAccountType	Account Type		200
   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. Double-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                string strCustomers = string.Empty;
                List<Customer> Customers = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string strAccountsTypes = string.Empty;
                List<AccountType> accountsTypes = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        Customers = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        lvwCustomers.Items.Clear();
    
                        foreach (Customer wm in Customers)
                        {
                            ListViewItem lviCustomer = new ListViewItem(wm.CustomerId.ToString());
    
                            lviCustomer.SubItems.Add(wm.AccountNumber);
                            lviCustomer.SubItems.Add(wm.AccountName);
                            lviCustomer.SubItems.Add(wm.MeterNumber);
    
                            TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                            strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                            accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                            foreach (AccountType at in accountsTypes)
                            {
                                if (wm.AccountType == at.TypeCode)
                                {
                                    lviCustomer.SubItems.Add(string.Concat(at.TypeCode, " - ", at.TypeDecription));
                                }
                            }
                            
                            lviCustomer.SubItems.Add(wm.Address);
                            lviCustomer.SubItems.Add(wm.City);
                            lviCustomer.SubItems.Add(wm.County);
                            lviCustomer.SubItems.Add(wm.State);
                            lviCustomer.SubItems.Add(wm.ZIPCode);
                            lvwCustomers.Items.Add(lviCustomer);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add a button to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnCustomers	C&ustomers...	Times New Roman, 24pt, style=Bold

14. Double-click the C&ustomers
15. Impliment the event as follows:

    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");
    
                // Repository.CreateAccountsTypes();
                // Repository.CreateWaterMeters();
            }
    
            private void btnCustomers_Click(object sender, EventArgs e)
            {
                Customers.Central central = new();
    
                central.Show();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

A New Customer Account

To use the services of a water distribution company, a customer must have an account. We are going to create a form that an employee can use to establish an account for a new customer.

Practical Learning: Creating a Customer Account

1. To create a form, in the Solution Explorer, right-click the WaterMeters folder -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Create 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
   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
   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
   Label			Customer Id:&
   TextBox		txtCustomerId
   Button		btnSaveCustomerAccount	S&ave Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. Using the Properties window, change some characteristics of the form as follows:

   FormBorderStyle: FixedDialog
   Text:            Stellar Water Point - Create Customer Account
   StartPosition:   CenterScreen
   AcceptButton:    btnSaveCustomerAccount
   CancelButton:    btnCancel

6. Double-click an unoccupied area of the form to generate its Load event
7. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.Customers
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void SetCustomerId()
           {
               string strCustomers = string.Empty;
               List<Customer> Customers = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               int CustomerId = 0;
   
               if (fiCustomers.Exists == true)
               {
   
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       Customers = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       foreach (Customer wm in Customers)
                       {
                           CustomerId = wm.CustomerId;
                       }
                   }
               }
   
               txtCustomerId.Text = (CustomerId + 1).ToString();
           }
   
           private void SetAccountsTypes()
           {
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                   }
               }
           }
   
           private void Create_Load(object sender, EventArgs e)
           {
               SetCustomerId();
               SetAccountsTypes();
           }
           
       }
   }

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

   private void btnFindWaterMeter_Click(object sender, EventArgs e)
   {
       if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
       {
           MsgBox.Show("You must type a valid meter number, " +
                       "and then click the Find Water Meter button.");
           return;
       }
   
       string strWaterMeters = string.Empty;
       List<WaterMeter> waterMeters = new List<WaterMeter>();
       string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
       FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
       if (fiWaterMeters.Exists == true)
       {
           strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
           waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
           foreach (WaterMeter meter in waterMeters)
           {
               if (meter.MeterNumber == mtbMeterNumber.Text)
               {
                   txtMeterDetails.Text = meter.WaterMeterId.ToString() + " - " +
                                          meter.Make + " " +
                                          meter.Model +
                                          " (Meter Size: " + meter.MeterSize + ")";
               }
           }
       }
   }

10. In the Solution Explorer, below the Customers folder, double-click Central.cs
11. From the Toolbox, add a button to the form below the list view
12. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details
    Button		btnNewCustomerAccount	&New Customer Account...

13. On the Central form, double-click the New Customer Account button
14. Implement the event as follows:

    private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
    {
        Create create = new();
    
        if (create.ShowDialog() == DialogResult.OK)
        {
            if(create.mtbAccountNumber.Text.Replace("-", "").Trim().Equals(""))
            {
                MsgBox.Show("You must provide an account number for a new customer. " +
                                "Otherwise, the account cannot be created.");
                return;
            }
    
            if (create.mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
            {
                MsgBox.Show("You must type a valid meter number to associate " +
                            "a water meter to a customer's account. After providing " +
                            "a meter number, click the Find Water Meter button.");
                return;
            }
    
            string strCustomers = string.Empty;
            List<Customer> clients = new List<Customer>();
            string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
            FileInfo fiCustomers = new FileInfo(fileCustomers);
    
            if (fiCustomers.Exists == true)
            {
                strCustomers = File.ReadAllText(fiCustomers.FullName);
                clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
            }
    
            Customer client = new Customer()
            {
                CustomerId = int.Parse(create.txtCustomerId.Text),
                AccountNumber = create.mtbAccountNumber.Text,
                AccountName = create.txtAccountName.Text,
                MeterNumber = create.mtbMeterNumber.Text,
                AccountType = create.cbxAccountsTypes.Text.Substring(0, 3),
                Address = create.txtAddress.Text,
                City = create.txtCity.Text,
                County = create.txtCounty.Text,
                State = create.txtState.Text,
                ZIPCode = create.mtbZIPCode.Text
            };
    
            clients.Add(client);
    
            JsonSerializerOptions options = new JsonSerializerOptions();
            options.WriteIndented = true;
    
            string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
            File.WriteAllText(fiCustomers.FullName, jsCustomers);
        }
    
        ShowCustomers();
    }

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

    

16. On the Water Distribution form, click the Customers button:

    

17. On the Central form of the customers, click the Create Customer Account button:

    

18. In the account # text box, type 9279-570-8394
19. In the meter # text box, type 799-528-461
20. Click the Find water meter button
21. 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

    

22. Click Save Customer Account
23. 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

    

24. Close the forms and return to your programming environment

Customer Account Details

When a customer account has been created, at any time, an employee may want to simply review such an account. Our application needs a form for that.

Practical Learning: Showing Customer Account

1. To create a form, in the Solution Explorer, right-click Customers -> 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
   Label			Customer Id:&:
   TextBox		txtCustomerId		Enabled: False
   Button		btnClose	&Close

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.Customers
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
               {
                   MsgBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.");
                   return;
               }
   
               string strCustomers = string.Empty;
               string strAccountType = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtCustomerId.Text = client.CustomerId.ToString();
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           strAccountType = 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)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   IEnumerable<AccountType> actType = from category
                                                      in types
                                                      where category.TypeCode == strAccountType
                                                      select category;
   
                   
                   foreach (AccountType type in types)
                   {
                       txtAccountType.Text = $"{type.TypeCode } - {type.TypeDecription}";
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

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

   private void btnClose_Click(object sender, EventArgs e)
   {
       Close();
   }

9. In the Solution Explorer, below the Customers folder, double-click Central.cs to open its form
10. From the Toolbox, add a button to the form below the list view and to the right of the New Customer Account button
11. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	No Change
    Button		No Change	No Change
    Button		btnCustomerAccountDetails	Customer Account &Details...

12. Double-click the Customer Account &Details button
13. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.ShowDialog();
    
                ShowCustomers();
            }
        }
    }

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

    

15. On the Water Distribution form, click the Customers button
16. On the Central form of the customers form, click the Customer Account &Details button:

    

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

    

19. Close the forms and return to your programming environment

Editing a Customer Account

When a piece of information has changed about a customer, an employee should update the customer account. We will provide a for such an operation.

Practical Learning: Editing a Customer Account

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	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
   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
   Label			Customer Id:&:
   TextBox		txtCustomerId		Enabled: False
   Button		btnUpdateCustomerAccount	&Update Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. Double-click an unoccupied area of the form to generate its Load event
6. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void Editor_Load(object sender, EventArgs e)
           {
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                   }
               }
           }
       }
   }

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void Editor_Load(object sender, EventArgs e)
           {
               . . .
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
               {
                   MsgBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.");
                   return;
               }
   
               string strCustomers = string.Empty;
               string strAccountType = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtCustomerId.Text = client.CustomerId.ToString();
                           txtAccountName.Text = client.AccountName;
                           mtbMeterNumber.Text = client.MeterNumber;
                           strAccountType = client.AccountType!;
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           mtbZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (mtbAccountNumber.Text!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == mtbMeterNumber.Text
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   IEnumerable<AccountType> actType = from category
                                                      in types
                                                      where category.TypeCode == strAccountType
                                                      select category;
   
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Text = $"{type.TypeCode} - {type.TypeDecription}";
                   }
               }
           }
       }
   }

9. Return to the form and double-click the Find Water Meter button
10. Change the document as follows:

    private void btnFindWaterMeter_Click(object sender, EventArgs e)
    {
        if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
        {
            MsgBox.Show("You must type a valid meter number, " +
                        "and then click the Find Water Meter button.");
            return;
        }
    
        string strWaterMeters = string.Empty;
        List<WaterMeter> waterMeters = new List<WaterMeter>();
        string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
        FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
        if (fiWaterMeters.Exists == true)
        {
            strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
            waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
            foreach (WaterMeter meter in waterMeters)
            {
                if (meter.MeterNumber == mtbMeterNumber.Text)
                {
                    txtMeterDetails.Text = meter.Make + " " +
                                           meter.Model +
                                           " (Meter Size: " + meter.MeterSize + ")";
                }
            }
        }
    }

11. Return to the form and double-click the Update Water Meter button
12. Change the document as follows:

    private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrEmpty(mtbAccountNumber.Text))
        {
            MsgBox.Show("Please enter an account number for a customer. " +
                        "You can then click the Find Customer Account button " +
                        "to indicate the customer whose account you want o update.");
            return;
        }
    
        if (string.IsNullOrEmpty(mtbMeterNumber.Text))
        {
            MsgBox.Show("You must type a valid meter number, " +
                        "and then click the Find Water Meter button.");
            return;
        }
    
        string strCustomers    = string.Empty;
        List<Customer> clients = new List<Customer>();
        string fileCustomers   = @"C:\Stellar Water Point2\Customers.json";
    
        FileInfo fiCustomers   = new FileInfo(fileCustomers);
    
        if (fiCustomers.Exists == true)
        {
            strCustomers       = File.ReadAllText(fiCustomers.FullName);
            clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
            Customer? customer = clients.Find(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
            if (customer is not null)
            {
                customer.CustomerId    = int.Parse(txtCustomerId.Text);
                customer.AccountNumber = mtbAccountNumber.Text;
                customer.AccountName   = txtAccountName.Text;
                customer.MeterNumber   = mtbMeterNumber.Text;
                customer.AccountType   = cbxAccountsTypes.Text.Substring(0, 3);
                customer.Address       = txtAddress.Text;
                customer.City          = txtCity.Text;
                customer.County        = txtCounty.Text;
                customer.State         = txtState.Text;
                customer.ZIPCode       = mtbZIPCode.Text;
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                File.WriteAllText(fiCustomers.FullName, jsCustomers);
            }
        }
    
        Close();
    }

13. Return to the form and double-click the Close button
14. Change the document as follows:

    using StellarWaterPoint2.Models;
    using System.Diagnostics.Metrics;
    using System.Net;
    using System.Reflection.Emit;
    using System.Text.Json;
    using static System.Windows.Forms.AxHost;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void Editor_Load(object sender, EventArgs e)
            {
                string strAccountsTypes = string.Empty;
                List<AccountType> types = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiAccountsTypes.Exists == true)
                {
                    strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                    types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                    foreach (AccountType type in types)
                    {
                        cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                    }
                }
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
                {
                    MsgBox.Show("You must type a valid account number of a customer, " +
                                    "and then click the Find Customer Account button.");
                    return;
                }
    
                string strCustomers = string.Empty;
                string strAccountType = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = from consumer
                                                          in clients
                                                          where consumer.AccountNumber == mtbAccountNumber.Text
                                                          select consumer;
    
                        foreach (Customer client in customers)
                        {
                            txtCustomerId.Text = client.CustomerId.ToString();
                            txtAccountName.Text = client.AccountName;
                            mtbMeterNumber.Text = client.MeterNumber;
                            strAccountType = client.AccountType!;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            mtbZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (mtbAccountNumber.Text!.Length > 0)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = from measure
                                                         in waterMeters
                                                         where measure.MeterNumber == mtbMeterNumber.Text
                                                         select measure;
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
    
                string strAccountsTypes = string.Empty;
                List<AccountType> types = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiAccountsTypes.Exists == true)
                {
                    strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                    types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                    IEnumerable<AccountType> actType = from category
                                                       in types
                                                       where category.TypeCode == strAccountType
                                                       select category;
    
    
                    foreach (AccountType type in types)
                    {
                        cbxAccountsTypes.Text = $"{type.TypeCode} - {type.TypeDecription}";
                    }
                }
            }
    
            private void btnFindWaterMeter_Click(object sender, EventArgs e)
            {
                if (mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
                {
                    MsgBox.Show("You must type a valid meter number, " +
                                "and then click the Find Water Meter button.");
                    return;
                }
    
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                    waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                    foreach (WaterMeter meter in waterMeters)
                    {
                        if (meter.MeterNumber == mtbMeterNumber.Text)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MsgBox.Show("Please enter an account number for a customer. " +
                                "You can then click the Find Customer Account button " +
                                "to indicate the customer whose account you want o update.");
                    return;
                }
    
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MsgBox.Show("You must type a valid meter number, " +
                                "and then click the Find Water Meter button.");
                    return;
                }
    
                string strCustomers    = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers   = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers   = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    strCustomers       = File.ReadAllText(fiCustomers.FullName);
                    clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                    Customer? customer = clients.Find(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
                    if (customer is not null)
                    {
                        customer.CustomerId    = int.Parse(txtCustomerId.Text);
                        customer.AccountNumber = mtbAccountNumber.Text;
                        customer.AccountName   = txtAccountName.Text;
                        customer.MeterNumber   = mtbMeterNumber.Text;
                        customer.AccountType   = cbxAccountsTypes.Text.Substring(0, 3);
                        customer.Address       = txtAddress.Text;
                        customer.City          = txtCity.Text;
                        customer.County        = txtCounty.Text;
                        customer.State         = txtState.Text;
                        customer.ZIPCode       = mtbZIPCode.Text;
    
                        JsonSerializerOptions options = new JsonSerializerOptions();
                        options.WriteIndented = true;
    
                        string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                        File.WriteAllText(fiCustomers.FullName, jsCustomers);
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

15. In the Solution Explorer, below the Customers folder, double-click Central.cs
16. From the Toolbox, add a button to the form below the list view and on the right side of the Customer Account Editor button
17. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	No Change
    Button		btnNewCustomerAccount	No Change
    Button		btnCustomerAccountDetails	No Change
    Button		btnUpdateCustomerAccount	&Update Customer Account...

18. Display the Central form of the Customers folder
19. Double-click the Update Customer Account button
20. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnEditCustomerAccount_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowCustomers();
            }
        }
    }

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

    

22. On the main form of the application, click the Customers button:

    

23. Click the Edit Customer Account button:

    

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

    

26. Change the values as follows:

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

    

27. Click the Update Customer Account button:

    

28. Close the forms and return to your programming environment

Deleting a Customer Account from the Database

If an employee realizes that a customer account must not exist anymore, the employee can delete that account. We will provide a form for such an operation.

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 tollows:

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.Customers
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
               {
                   MsgBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.");
                   return;
               }
   
               string strCustomers = string.Empty;
               string strAccountType = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtCustomerId.Text = client.CustomerId.ToString();
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           strAccountType = 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)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
   
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   IEnumerable<AccountType> actType = from category
                                                      in types
                                                      where category.TypeCode == strAccountType
                                                      select category;
   
   
                   foreach (AccountType type in types)
                   {
                       txtAccountType.Text = $"{type.TypeCode} - {type.TypeDecription}";
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Delete Customer Account button
8. Implement the event as tollows:

   private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
   {
       if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
       {
           MsgBox.Show("You must type a valid account number of a customer, " +
                           "and then click the Find Customer Account button. " +
                           "Only then can you delete an customer account.");
           return;
       }
   
       string strCustomers = string.Empty;
       List<Customer> clients = new List<Customer>();
       string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
       FileInfo fiCustomers = new FileInfo(fileCustomers);
   
       if (fiCustomers.Exists == true)
       {
           strCustomers = File.ReadAllText(fiCustomers.FullName);
           clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
           Customer client = clients.Find(acnt => acnt.AccountNumber == mtbAccountNumber.Text)!;
   
           if (client is not null)
           {
               if (MsgBox.Question("Are you sure you want to delete this customer's account " +
                                   "(you cannot undo the action)?") == Answer.Yes)
               {
                   clients.Remove(client);
   
                   JsonSerializerOptions options = new JsonSerializerOptions();
                   options.WriteIndented = true;
   
                   string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                   File.WriteAllText(fiCustomers.FullName, jsCustomers);
   
                   MsgBox.Show("The customer's account has been deleted from our system.");
               }
           }
       }
   
       Close();
   }

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

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
                {
                    MsgBox.Show("You must type a valid account number of a customer, " +
                                    "and then click the Find Customer Account button.");
                    return;
                }
    
                string strCustomers = string.Empty;
                string strAccountType = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = from consumer
                                                          in clients
                                                          where consumer.AccountNumber == mtbAccountNumber.Text
                                                          select consumer;
    
                        foreach (Customer client in customers)
                        {
                            txtCustomerId.Text = client.CustomerId.ToString();
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
                            strAccountType = 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)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = from measure
                                                         in waterMeters
                                                         where measure.MeterNumber == strMeterNumber
                                                         select measure;
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
    
                string strAccountsTypes = string.Empty;
                List<AccountType> types = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiAccountsTypes.Exists == true)
                {
                    strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                    types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                    IEnumerable<AccountType> actType = from category
                                                       in types
                                                       where category.TypeCode == strAccountType
                                                       select category;
    
    
                    foreach (AccountType type in types)
                    {
                        txtAccountType.Text = $"{type.TypeCode} - {type.TypeDecription}";
                    }
                }
            }
    
            private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
            {
                if (mtbAccountNumber.Text.Replace("-", "").Trim() == "")
                {
                    MsgBox.Show("You must type a valid account number of a customer, " +
                                "and then click the Find Customer Account button. " +
                                "Only then can you delete an customer account.");
                    return;
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    strCustomers = File.ReadAllText(fiCustomers.FullName);
                    clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                    Customer client = clients.Find(acnt => acnt.AccountNumber == mtbAccountNumber.Text)!;
    
                    if (client is not null)
                    {
                        if (MsgBox.Question("Are you sure you want to delete this customer's account " +
                                            "(you cannot undo the action)?") == Answer.Yes)
                        {
                            clients.Remove(client);
    
                            JsonSerializerOptions options = new JsonSerializerOptions();
                            options.WriteIndented = true;
    
                            string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                            File.WriteAllText(fiCustomers.FullName, jsCustomers);
    
                            MsgBox.Show("The customer's account has been deleted from our system.");
                        }
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

11. In the Solution Explorer, below the Customers folder, double-click Central.cs
12. From the Toolbox, add two buttons to the form below the list view and on the right side of the Update Customer Account button
13. Change the characteristics of the buttons as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details Anchor: Top, Bottom, Left, Right
    Button		btnCreateCustomerAccount	Create Customer &Account.... Anchor: Bottom, Right
    Button		btnCustomerAccountDetails	Customer Account &Details... Anchor: Bottom, Right
    Button		btnEditCustomerAccount	&Edit Customer Account... Anchor: Bottom, Right
    Button		btnDeleteCustomerAccount	&Delete Customer Account... Anchor: Bottom, Right
    Button		btnClose	&Close Anchor: Bottom, Right

14. On the form, double-click the Delete Customer Account button
15. Return to the Central form of the water meters and double-click the Close button
16. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                string strCustomers = string.Empty;
                List<Customer> Customers = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string strAccountsTypes = string.Empty;
                List<AccountType> accountsTypes = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        Customers = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        lvwCustomers.Items.Clear();
    
                        foreach (Customer wm in Customers)
                        {
                            ListViewItem lviCustomer = new ListViewItem(wm.CustomerId.ToString());
    
                            lviCustomer.SubItems.Add(wm.AccountNumber);
                            lviCustomer.SubItems.Add(wm.AccountName);
                            lviCustomer.SubItems.Add(wm.MeterNumber);
    
                            TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                            strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                            accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                            foreach (AccountType at in accountsTypes)
                            {
                                if (wm.AccountType == at.TypeCode)
                                {
                                    lviCustomer.SubItems.Add(string.Concat(at.TypeCode, " - ", at.TypeDecription));
                                }
                            }
                            
                            lviCustomer.SubItems.Add(wm.Address);
                            lviCustomer.SubItems.Add(wm.City);
                            lviCustomer.SubItems.Add(wm.County);
                            lviCustomer.SubItems.Add(wm.State);
                            lviCustomer.SubItems.Add(wm.ZIPCode);
                            lvwCustomers.Items.Add(lviCustomer);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if(create.mtbAccountNumber.Text.Replace("-", "").Trim().Equals(""))
                    {
                        MsgBox.Show("You must provide an account number for a new customer. " +
                                        "Otherwise, the account cannot be created.");
                        return;
                    }
    
                    if (create.mtbMeterNumber.Text.Replace("-", "").Trim().Equals(string.Empty))
                    {
                        MsgBox.Show("You must type a valid meter number to associate " +
                                        "a water meter to a customer's account. After providing " +
                                        "a meter number, click the Find Water Meter button.");
                        return;
                    }
    
                    string strCustomers = string.Empty;
                    List<Customer> clients = new List<Customer>();
                    string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                    FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                    if (fiCustomers.Exists == true)
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
    
                    Customer client = new Customer()
                    {
                        CustomerId = int.Parse(create.txtCustomerId.Text),
                        AccountNumber = create.mtbAccountNumber.Text,
                        AccountName = create.txtAccountName.Text,
                        MeterNumber = create.mtbMeterNumber.Text,
                        AccountType = create.cbxAccountsTypes.Text.Substring(0, 3),
                        Address = create.txtAddress.Text,
                        City = create.txtCity.Text,
                        County = create.txtCounty.Text,
                        State = create.txtState.Text,
                        ZIPCode = create.mtbZIPCode.Text
                    };
    
                    clients.Add(client);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                    File.WriteAllText(fiCustomers.FullName, jsCustomers);
                }
    
                ShowCustomers();
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
    
            private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
            {
                Editor editor = new();
                
                editor.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
            {
                Delete delete = new();
    
                delete.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

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

    

18. On the Central form, click the Customers button:

    

19. On the Central form of the customers, click the Delete Customer Account button:

    

20. In the Account # text box, type 7080-583-5947
21. Click the Find Customer Account button:

    

22. Click the Delete Customer Account button

    

23. Read the text on the message box.
    On the message box, click Yes

    

24. In the same way, delete the other two records
25. Close the forms and return to your programming environment
26. Open the Customers.json file. Replace its contents with the following and save:

    [
      {
        "CustomerId": 1,
        "AccountNumber": "9279-570-8394",
        "AccountName": "Thomas Stones",
        "MeterNumber": "799-528-461",
        "AccountType": "RES",
        "Address": "10252 Broward Ave #D4",
        "City": "Frederick",
        "County": "Frederick",
        "State": "MD",
        "ZIPCode": "21703-4422"
      },
      {
        "CustomerId": 2,
        "AccountNumber": "4086-938-4783",
        "AccountName": "Bernotte Doughnuts",
        "MeterNumber": "580-742-825",
        "AccountType": "BUS",
        "Address": "10103 Hexagon Drv",
        "City": "Winterstown",
        "County": "York",
        "State": "PA",
        "ZIPCode": "17402-8818"
      },
      {
        "CustomerId": 3,
        "AccountNumber": "2068-258-9486",
        "AccountName": "Yollanda Training",
        "MeterNumber": "186-962-805",
        "AccountType": "UUO",
        "Address": "4819 East Munk Street",
        "City": "Whitehall",
        "County": "Fulton",
        "State": "PA",
        "ZIPCode": "17340-1188"
      },
      {
        "CustomerId": 4,
        "AccountNumber": "6986-829-3741",
        "AccountName": "Eyes Wide",
        "MeterNumber": "208-428-308",
        "AccountType": "BUS",
        "Address": "12087 Avencia Court #4D1",
        "City": "Silver Spring",
        "County": "Montgomery",
        "State": "MD",
        "ZIPCode": "20910-2288"
      },
      {
        "CustomerId": 5,
        "AccountNumber": "9947-374-2648",
        "AccountName": "Marianne Harrington",
        "MeterNumber": "862-715-006",
        "AccountType": "RES",
        "Address": "708 Correta Drv",
        "City": "Arlington",
        "County": "",
        "State": "VA",
        "ZIPCode": "22222-6060"
      },
      {
        "CustomerId": 6,
        "AccountNumber": "4293-802-8506",
        "AccountName": "Kelly Davids",
        "MeterNumber": "496-813-794",
        "AccountType": "RES",
        "Address": "938 East Panchot Str",
        "City": "Greenwood",
        "County": "Sussex",
        "State": "DE",
        "ZIPCode": "19950-4242"
      },
      {
        "CustomerId": 7,
        "AccountNumber": "6240-857-4965",
        "AccountName": "First Methodist Congregation",
        "MeterNumber": "739-777-749",
        "AccountType": "RES",
        "Address": "7702 Charles Road",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 8,
        "AccountNumber": "7928-131-4850",
        "AccountName": "Department of Public Affairs",
        "MeterNumber": "",
        "AccountType": "SGO",
        "Address": "",
        "City": "Hyattsville",
        "County": "Prince Georges",
        "State": "MD",
        "ZIPCode": "20783-2277"
      },
      {
        "CustomerId": 9,
        "AccountNumber": "1386-949-2058",
        "AccountName": "Watson Country Buffet",
        "MeterNumber": "296-837-495",
        "AccountType": "WAT",
        "Address": "4862 Wellington Street",
        "City": "Hammonton",
        "County": "Atlantic ",
        "State": "NJ",
        "ZIPCode": "08037-2828"
      },
      {
        "CustomerId": 10,
        "AccountNumber": "7943-686-9786",
        "AccountName": "Angel Bulzaides",
        "MeterNumber": "394-835-297",
        "AccountType": "RES",
        "Address": "10227 Old Harbor Drv",
        "City": "Elkview",
        "County": "Kanawha",
        "State": "WV",
        "ZIPCode": "25071-5858"
      },
      {
        "CustomerId": 11,
        "AccountNumber": "4820-375-2842",
        "AccountName": "Sun Communal",
        "MeterNumber": "392-494-572",
        "AccountType": "SGO",
        "Address": "748 Red Hills Rd",
        "City": "Roanoke",
        "County": "",
        "State": "VA",
        "ZIPCode": "24012-4824"
      },
      {
        "CustomerId": 12,
        "AccountNumber": "9618-579-2577",
        "AccountName": "Gerald Place",
        "MeterNumber": "847-252-246",
        "AccountType": "UUO",
        "Address": "3666 Hanchor Drv",
        "City": "Granville",
        "County": "Licking",
        "State": "OH",
        "ZIPCode": "43023-2777"
      },
      {
        "CustomerId": 13,
        "AccountNumber": "",
        "AccountName": "",
        "MeterNumber": "",
        "AccountType": "",
        "Address": "",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 14,
        "AccountNumber": "2037-495-8528",
        "AccountName": "Astral Sequence",
        "MeterNumber": "",
        "AccountType": "BUS",
        "Address": "12715 Eastern Gateway",
        "City": "Catonsville",
        "County": "Baltimore County",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 15,
        "AccountNumber": "6003-386-3955",
        "AccountName": "Mandiakandara Marmoudi",
        "MeterNumber": "374-886-284",
        "AccountType": "OTH",
        "Address": "539 Avalon Court",
        "City": "Greenwood",
        "County": "Sussex",
        "State": "DE",
        "ZIPCode": "19950-5550"
      },
      {
        "CustomerId": 16,
        "AccountNumber": "5294-859-7513",
        "AccountName": "Jeannette Schiller",
        "MeterNumber": "713-942-058",
        "AccountType": "RES",
        "Address": "10110 Winslow Ave",
        "City": "Mercerville",
        "County": "Mercer",
        "State": "NJ",
        "ZIPCode": "08619-7472"
      },
      {
        "CustomerId": 17,
        "AccountNumber": "9249-379-6848",
        "AccountName": "Country West Eatery",
        "MeterNumber": "588-279-663",
        "AccountType": "BUS",
        "Address": "8280 Sligo North Way",
        "City": "Albright",
        "County": "Preston",
        "State": "WV",
        "ZIPCode": "26519-6620"
      },
      {
        "CustomerId": 18,
        "AccountNumber": "5252-757-9595",
        "AccountName": "Sathyavanthara Khooni",
        "MeterNumber": "379-386-979",
        "AccountType": "RES",
        "Address": "4992 Preston Street",
        "City": "",
        "County": "",
        "State": "OH",
        "ZIPCode": ""
      },
      {
        "CustomerId": 19,
        "AccountNumber": "7080-583-5947",
        "AccountName": "Sunny Yard",
        "MeterNumber": "827-508-248",
        "AccountType": "WAT",
        "Address": "663 Sherry Wood East Street",
        "City": "Shimpstown",
        "County": "Franklin",
        "State": "PA",
        "ZIPCode": "17236-2626"
      },
      {
        "CustomerId": 20,
        "AccountNumber": "8027-304-6829",
        "AccountName": "Anthony Clarcksons",
        "MeterNumber": "837-806-836",
        "AccountType": "RES",
        "Address": "904 Augusta Drive",
        "City": "Blackbird",
        "County": "New Castle",
        "State": "DE",
        "ZIPCode": "19734-8822"
      },
      {
        "CustomerId": 21,
        "AccountNumber": "6699-396-2905",
        "AccountName": "Spencer Reuter",
        "MeterNumber": "649-373-505",
        "AccountType": "RES",
        "Address": "2850 Burnsweak Avenue",
        "City": "Silver Spring",
        "County": "Montgomery",
        "State": "MD",
        "ZIPCode": "20910-4044"
      },
      {
        "CustomerId": 22,
        "AccountNumber": "1827-395-0203",
        "AccountName": "Watson Country Buffet",
        "MeterNumber": "470-628-850",
        "AccountType": "WAT",
        "Address": "10331 Chryswell Road",
        "City": "Washington",
        "County": "",
        "State": "DC",
        "ZIPCode": "20008-2426"
      },
      {
        "CustomerId": 23,
        "AccountNumber": "5862-736-9741",
        "AccountName": "Eastern Cage",
        "MeterNumber": "",
        "AccountType": "BUS",
        "Address": "2039 Night Stand Court",
        "City": "Hammonton",
        "County": "",
        "State": "NJ",
        "ZIPCode": ""
      },
      {
        "CustomerId": 24,
        "AccountNumber": "3947-957-4958",
        "AccountName": "Patsil Industries",
        "MeterNumber": "747-581-379",
        "AccountType": "BUS",
        "Address": "10348 Larrens Drive",
        "City": "Baltimore",
        "County": "Baltimore",
        "State": "MD",
        "ZIPCode": "21215-2222"
      },
      {
        "CustomerId": 25,
        "AccountNumber": "2836-485-9699",
        "AccountName": "Red Oak High School",
        "MeterNumber": "379-386-979",
        "AccountType": "SGO",
        "Address": "442 Donham Road",
        "City": "Silver Spring",
        "County": "Montgomery",
        "State": "MD",
        "ZIPCode": "20910-8822"
      },
      {
        "CustomerId": 26,
        "AccountNumber": "5938-074-5293",
        "AccountName": "Park and Roll",
        "MeterNumber": "592-824-957",
        "AccountType": "SGO",
        "Address": "582G Dunhill Avenue",
        "City": "Lanham",
        "County": "Prince Georges",
        "State": "MD",
        "ZIPCode": "20706-8284"
      },
      {
        "CustomerId": 27,
        "AccountNumber": "3028-502-9418",
        "AccountName": "Spencer Kershaw",
        "MeterNumber": "186-959-757",
        "AccountType": "RES",
        "Address": "338C Grayson Street",
        "City": "Gatchellville",
        "County": "York",
        "State": "PA",
        "ZIPCode": "17352-6464"
      },
      {
        "CustomerId": 28,
        "AccountNumber": "9684-759-2227",
        "AccountName": "Country West Eatery",
        "MeterNumber": "928-317-924",
        "AccountType": "BUS",
        "Address": "",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 29,
        "AccountNumber": "2974-972-8139",
        "AccountName": "Paul Arnette",
        "MeterNumber": "295-770-695",
        "AccountType": "OTH",
        "Address": "8127 Bledsoe Str",
        "City": "Hyattsville",
        "County": "Prince Georges",
        "State": "MD",
        "ZIPCode": "20783-5858"
      },
      {
        "CustomerId": 30,
        "AccountNumber": "2758-493-7249",
        "AccountName": "Hervey Smile",
        "MeterNumber": "293-924-869",
        "AccountType": "WAT",
        "Address": "12973 Sonaa Street #E42",
        "City": "Silver Spring",
        "County": "Montgomery",
        "State": "MD",
        "ZIPCode": "20910-4488"
      },
      {
        "CustomerId": 31,
        "AccountNumber": "9337-947-3664",
        "AccountName": "Awesome Aid",
        "MeterNumber": "649-358-184",
        "AccountType": "SGO",
        "Address": "",
        "City": "Bellefontaine",
        "County": "",
        "State": "OH",
        "ZIPCode": ""
      },
      {
        "CustomerId": 32,
        "AccountNumber": "7518-302-6895",
        "AccountName": "Grace Brenner",
        "MeterNumber": "207-964-835",
        "AccountType": "BUS",
        "Address": "4299 Peachtree Court",
        "City": "Rockville",
        "County": "Montgomery",
        "State": "MD",
        "ZIPCode": "20853-1888"
      },
      {
        "CustomerId": 33,
        "AccountNumber": "2937-947-3008",
        "AccountName": "Jeffrey Maney",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 34,
        "AccountNumber": "7028-405-9381",
        "AccountName": "Valley Services",
        "MeterNumber": "306-842-497",
        "AccountType": "WAT",
        "Address": "613 Meadowhill Road",
        "City": "Alonzaville",
        "County": "Shenandoah",
        "State": "VA",
        "ZIPCode": "22664-8080"
      },
      {
        "CustomerId": 35,
        "AccountNumber": "5293-957-3395",
        "AccountName": "Wellway Community Center",
        "MeterNumber": "386-468-057",
        "AccountType": "RES",
        "Address": "10484 Greenway Avenue",
        "City": "Mt Storm",
        "County": "Grant",
        "State": "WV",
        "ZIPCode": "26739-7700"
      },
      {
        "CustomerId": 36,
        "AccountNumber": "2038-413-9680",
        "AccountName": "Eastern Friandise",
        "MeterNumber": "938-725-869",
        "AccountType": "BUS",
        "Address": "2075 Rose Hills Avenue",
        "City": "Washington",
        "County": "",
        "State": "DC",
        "ZIPCode": "20004-2626"
      },
      {
        "CustomerId": 37,
        "AccountNumber": "7484-744-9708",
        "AccountName": "Amidou Gomah",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "14118 Yellow Burrough Blvd",
        "City": "Philadelphia",
        "County": "",
        "State": "PA",
        "ZIPCode": ""
      },
      {
        "CustomerId": 38,
        "AccountNumber": "3792-853-6885",
        "AccountName": "Department of Public Affairs",
        "MeterNumber": "595-753-147",
        "AccountType": "",
        "Address": "",
        "City": "Upper Marlboro",
        "County": "Prince George County",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 39,
        "AccountNumber": "8282-777-8282",
        "AccountName": "Garland Hotel",
        "MeterNumber": "938-275-294",
        "AccountType": "BUS",
        "Address": "4222 Extell Ave",
        "City": "Cambridge",
        "County": "",
        "State": "MD",
        "ZIPCode": "21613-2288"
      },
      {
        "CustomerId": 40,
        "AccountNumber": "5975-863-7057",
        "AccountName": "Single Connection",
        "MeterNumber": "288-427-585",
        "AccountType": "BUS",
        "Address": "",
        "City": "Mansfield",
        "County": "",
        "State": "OH",
        "ZIPCode": "44903-3030"
      },
      {
        "CustomerId": 41,
        "AccountNumber": "2499-636-4444",
        "AccountName": "Bryanna Spencer",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "6282 Sheppherd Str",
        "City": "",
        "County": "Anne Arundel",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 42,
        "AccountNumber": "2842-585-7260",
        "AccountName": "District Community Reserves",
        "MeterNumber": "349-725-848",
        "AccountType": "SGO",
        "Address": "3280 Hopewell Street, NE",
        "City": "Washington",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 43,
        "AccountNumber": "9282-794-7937",
        "AccountName": "Yashua Yáñés",
        "MeterNumber": "392-494-572",
        "AccountType": "RES",
        "Address": "10214 Monroe Ave",
        "City": "Easton",
        "County": "",
        "State": "MD",
        "ZIPCode": ""
      },
      {
        "CustomerId": 44,
        "AccountNumber": "6837-468-4750",
        "AccountName": "Miguel Altieri",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "10941 Patriot Blvd",
        "City": "Crenshaw",
        "County": "Jefferson",
        "State": "PA",
        "ZIPCode": "15824-6628"
      },
      {
        "CustomerId": 45,
        "AccountNumber": "2847-597-2829",
        "AccountName": "Jameson",
        "MeterNumber": "379-386-979",
        "AccountType": "WAT",
        "Address": "7373 Gold Town Rd",
        "City": "",
        "County": "",
        "State": "WV",
        "ZIPCode": ""
      },
      {
        "CustomerId": 46,
        "AccountNumber": "6381-748-2222",
        "AccountName": "Up Eyes",
        "MeterNumber": "",
        "AccountType": "BUS",
        "Address": "4149 Deerfield Str",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 47,
        "AccountNumber": "4968-274-9638",
        "AccountName": "Annette Wald",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "11441  Eastern Friendshi Rd",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 48,
        "AccountNumber": "8384-708-2941",
        "AccountName": "Department of Environment Affairs",
        "MeterNumber": "",
        "AccountType": "SGO",
        "Address": "",
        "City": "",
        "County": "",
        "State": "OH",
        "ZIPCode": ""
      },
      {
        "CustomerId": 49,
        "AccountNumber": "3728-138-2947",
        "AccountName": "Marie Rath",
        "MeterNumber": "",
        "AccountType": "",
        "Address": "8802 Atlantic Ave",
        "City": "",
        "County": "",
        "State": "PA",
        "ZIPCode": ""
      },
      {
        "CustomerId": 50,
        "AccountNumber": "1793-857-9413",
        "AccountName": "Body Care",
        "MeterNumber": "",
        "AccountType": "WAT",
        "Address": "",
        "City": "Ocean City",
        "County": "",
        "State": "NJ",
        "ZIPCode": ""
      },
      {
        "CustomerId": 51,
        "AccountNumber": "6028-695-2068",
        "AccountName": "Ronald Glassman",
        "MeterNumber": "468-359-486",
        "AccountType": "BUS",
        "Address": "",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 52,
        "AccountNumber": "4069-37-49728",
        "AccountName": "Lucette Wash N Dry",
        "MeterNumber": "",
        "AccountType": "WAT",
        "Address": "8812 Lawrence Ave",
        "City": "",
        "County": "",
        "State": "NW",
        "ZIPCode": ""
      },
      {
        "CustomerId": 53,
        "AccountNumber": "9616-283-7249",
        "AccountName": "Department of Public Affairs",
        "MeterNumber": "",
        "AccountType": "SGO",
        "Address": "13006 Blueberry Ave",
        "City": "Greenbelt",
        "County": "",
        "State": "MD",
        "ZIPCode": "20770-2040"
      },
      {
        "CustomerId": 54,
        "AccountNumber": "2829-516-8353",
        "AccountName": "Richard Eghert",
        "MeterNumber": "",
        "AccountType": "RES",
        "Address": "662 Placido Road",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 55,
        "AccountNumber": "6296-875-9607",
        "AccountName": "Country West Eatery",
        "MeterNumber": "",
        "AccountType": "BUS",
        "Address": "837 Larrenson Drv",
        "City": "Cumberland",
        "County": "",
        "State": "MD",
        "ZIPCode": ""
      },
      {
        "CustomerId": 56,
        "AccountNumber": "9684-794-6379",
        "AccountName": "Eye Care",
        "MeterNumber": "",
        "AccountType": "BUS",
        "Address": "8626 Cameron Str",
        "City": "",
        "County": "",
        "State": "",
        "ZIPCode": ""
      },
      {
        "CustomerId": 57,
        "AccountNumber": "2405-839-5820",
        "AccountName": "Watson Country Buffet",
        "MeterNumber": "",
        "AccountType": "WAT",
        "Address": "",
        "City": "Harrisburg",
        "County": "",
        "State": "PA",
        "ZIPCode": ""
      }
    ]

Water Bills

Introduction

A water bill is an intermediary document between the water distribution company and a consumer. We will create the classes, forms, and operations to present that information.

Practical Learning: Introducing Water Bills

1. To create a folder, in the Solution Explorer, right-click the StellarWaterPoint2 project -> Add -> New Folder
2. Type WaterBills as the name of the folder
3. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
4. Type WaterBill as the Name of the file
5. Click Add
6. Define the class as follows:

   namespace StellarWaterPoint2.Models
   {
       public class WaterBill
       {
           public int      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; }
       }
   }

7. To create another class, in the Solution Explorer, right-click Models -> Add -> Class...
8. Type WaterBillManager as the Name of the file
9. Click Add
10. Define the class as follows:

    namespace StellarWaterPoint2.Models
    {
        internal static class WaterBillManager
        {
            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);
    
                switch (acnt)
                {
                    case "RES":
                        results.tier1 = total * 39.35 / 10000.00;
                        results.tier2 = total * 18.25 / 10000.00;
                        results.tier3 = total * 11.65 / 10000.00;
                        break;
                    case "SGO":
                        results.tier1 = total * 41.38 / 10000.00;
                        results.tier2 = total * 15.26 / 10000.00;
                        results.tier3 = total * 8.13 / 10000.00;
                        break;
                    case "BUS":
                        results.tier1 = total * 51.25 / 10000.00;
                        results.tier2 = total * 34.65 / 10000.00;
                        results.tier3 = total * 15.10 / 10000.00;
                        break;
                    case "UUO":
                        results.tier1 = total * 25.00 / 10000.00;
                        results.tier2 = total * 35.00 / 10000.00;
                        results.tier3 = total * 40.00 / 10000.00;
                        break;
                    case "WAT":
                        results.tier1 = (total / 6) * 3 * 50.00 / 10000.00;
                        results.tier2 = (total / 6) * 2 * 35.00 / 10000.00;
                        results.tier3 = total * 15.00 / 10000.00;
                        break;
                    default:
                        results.tier1 = total * (48.00 / 10000.00);
                        results.tier2 = total * (32.00 / 10000.00);
                        results.tier3 = total * (20.00 / 10000.00);
                        break;
                }
    
                return results;
            }
    
            internal static double CalculateSewerCharges(string acnt, double total)
            {
                double result;
    
                if (acnt == "RES")
                {
                    result = total * 1.028641 / 100.00;
                }
                else if (acnt == "SGO")
                {
                    result = total * 4.162522 / 100.00;
                }
                else if (acnt == "BUS")
                {
                    result = total * 8.446369 / 100.00;
                }
                else if (acnt == "UUO")
                {
                    result = total * 10.622471 / 100.00;
                }
                else if (acnt == "WAT")
                {
                    result = total * 12.053152 / 100.00;
                }
                else // if (acnt == "OTH)"
                {
                    result = total * 9.206252 / 100.00;
                }
    
                return result;
            }
    
            internal static double CalculateEnvironmentCharges(string acnt, double total)
            {
                double result;
    
                switch (acnt)
                {
                    case "RES":
                        result = total * 0.004524;
                        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 * 0.006248;
                    case "SGO":
                        return total * 0.102246;
                    case "BUS":
                        return total * 0.155227;
                    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 * 0.035749,
                "SGO" => total * 0.044026,
                "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 * 0.007124,
                "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(15, 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)
            };
        }
    }

Showing Water Bills

A water distribution company has many records for water bills, and a typical water bill includes many pieces of information. We will create a form that displays a list of some pieces of information about a water bill.

Practical Learning: Showing 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. Double-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                string strCustomers = string.Empty;
                
                List<Customer> clients = new List<Customer>();
                
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                
                string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        lvwWaterBills.Items.Clear();
    
                        foreach (WaterBill invoice in bills)
                        {
                            ListViewItem lviWaterBill = new ListViewItem(invoice.WaterBillId.ToString());
    
                            lviWaterBill.SubItems.Add(invoice.BillNumber.ToString());
    
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == invoice.AccountNumber);
    
                            foreach (Customer cust in customer)
                            {
                                lviWaterBill.SubItems.Add(invoice.AccountNumber + " - " +
                                                          cust.AccountName +
                                                          ", Type: " + cust.AccountType![..3] +
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            lviWaterBill.SubItems.Add(invoice.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(invoice.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(invoice.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(invoice.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(invoice.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(invoice.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add two buttons to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnWaterBills	C&Water Bills...	Times New Roman, 24pt, style=Bold
    Button		btnClose	&Close	Times New Roman, 24pt, style=Bold

14. Double-click the &Water Bills button
15. Return to the form and double-click the Close button
16. Impliment the events as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2
    {
        public partial class WaterDistribution : Form
        {
            private void CreateWaterMeters()
            {
                List<WaterMeter> waterMeters = new List<WaterMeter>();
    
                waterMeters!.Add(new WaterMeter() { WaterMeterId =  1, MeterNumber = "392-494-572", Make = "Constance Technologies", Model = "TG-4822",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  2, MeterNumber = "938-725-869", Make = "Stanford Trend",         Model = "266G",     MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  3, MeterNumber = "588-279-663", Make = "Estellano",              Model = "NCF-226",  MeterSize = "4 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  4, MeterNumber = "186-962-805", Make = "Lansome",                Model = "2800",     MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  5, MeterNumber = "379-386-979", Make = "Planetra",               Model = "P-2020",   MeterSize = "4 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  6, MeterNumber = "580-742-825", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 3/4 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  7, MeterNumber = "849-351-444", Make = "Raynes Energica",        Model = "a1088",    MeterSize = "2 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  8, MeterNumber = "208-428-308", Make = "Constance Technologies", Model = "808D",     MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId =  9, MeterNumber = "738-588-249", Make = "Warrington",             Model = "W4242",    MeterSize = "5/8 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 10, MeterNumber = "496-813-794", Make = "Estellano",              Model = "NCF-226",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 11, MeterNumber = "862-715-006", Make = "Warrington",             Model = "W-4040",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 12, MeterNumber = "649-358-184", Make = "Raynes Energica",        Model = "b1700",    MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 13, MeterNumber = "928-317-924", Make = "Gongola",                Model = "GN1000",   MeterSize = "2 Inch"       });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 14, MeterNumber = "595-753-147", Make = "Grass Grill",            Model = "CRC-1000", MeterSize = "1 Inch"       });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 15, MeterNumber = "799-528-461", Make = "Kensa Sons",             Model = "K-584-L",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 16, MeterNumber = "386-468-057", Make = "Estellano",              Model = "NCF-226",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 17, MeterNumber = "938-275-294", Make = "Constance Technologies", Model = "TT-8822",  MeterSize = "4 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 18, MeterNumber = "288-427-585", Make = "Planetra",               Model = "P-2020",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 19, MeterNumber = "394-835-297", Make = "Raynes Energica",        Model = "i2022",    MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 20, MeterNumber = "847-252-246", Make = "Master Stream",          Model = "2000-MS",  MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 21, MeterNumber = "349-725-848", Make = "Planetra",               Model = "P-8000",   MeterSize = "4 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 22, MeterNumber = "713-942-058", Make = "Master Stream",          Model = "3366-MS",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 23, MeterNumber = "747-581-379", Make = "Warrington",             Model = "W4242",    MeterSize = "5/8 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 24, MeterNumber = "582-755-263", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 Inch"       });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 25, MeterNumber = "827-260-758", Make = "Raynes Energica",        Model = "a1088",    MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 26, MeterNumber = "837-806-836", Make = "Lansome",                Model = "7400",     MeterSize = "5/8 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 27, MeterNumber = "207-964-835", Make = "Constance Technologies", Model = "TG-6220",  MeterSize = "5/8 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 28, MeterNumber = "296-837-495", Make = "Raynes Energica",        Model = "QG505",    MeterSize = "4 Inches"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 29, MeterNumber = "468-359-486", Make = "Grass Grill",            Model = "KLP-8822", MeterSize = "1-1/4 Inch"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 30, MeterNumber = "931-486-003", Make = "Planetra",               Model = "P-2020",   MeterSize = "1/2 Inch"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 31, MeterNumber = "483-770-648", Make = "Warren",                 Model = "WWW",      MeterSize = "0.1 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 32, MeterNumber = "592-824-957", Make = "Kensa Sons",             Model = "D-497-H",  MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 33, MeterNumber = "293-835-704", Make = "Gongola",                Model = "GOL1000",  MeterSize = "1/2 Inch"     });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 34, MeterNumber = "739-777-749", Make = "Warrington",             Model = "W2200W",   MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 35, MeterNumber = "374-886-284", Make = "Raynes Energica",        Model = "i2022",    MeterSize = "3/4 Inches"   });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 36, MeterNumber = "186-959-757", Make = "Kensa Sons",             Model = "M-686-G",  MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 37, MeterNumber = "594-827-359", Make = "Planetra",               Model = "P-8000",   MeterSize = "1 Inch"       });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 38, MeterNumber = "394-739-242", Make = "Master Stream",          Model = "9393-TT",  MeterSize = "5/8 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 39, MeterNumber = "529-283-752", Make = "Constance Technologies", Model = "404T",     MeterSize = "3/4 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 40, MeterNumber = "295-770-695", Make = "Warrington",             Model = "W-2286",   MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 41, MeterNumber = "739-749-737", Make = "Kensa Sons",             Model = "KS2000A",  MeterSize = "1 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 42, MeterNumber = "947-528-317", Make = "Gondola",                Model = "GDL-5000", MeterSize = "1 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 43, MeterNumber = "630-207-055", Make = "Lansome",                Model = "2800",     MeterSize = "3/4 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 44, MeterNumber = "827-508-248", Make = "Standard Trend",         Model = "428T",     MeterSize = "3/4 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 45, MeterNumber = "293-924-869", Make = "Grass Grill",            Model = "CRC-2020", MeterSize = "1/2 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 46, MeterNumber = "928-247-580", Make = "Gondola",                Model = "GOL2000",  MeterSize = "0.34 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 47, MeterNumber = "682-537-380", Make = "Planetra",               Model = "P-2020",   MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 48, MeterNumber = "470-628-850", Make = "Estellano",              Model = "WRT-482",  MeterSize = "3/4 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 49, MeterNumber = "649-373-505", Make = "Constance Technologies", Model = "BD-7000",  MeterSize = "5/8 Inches" });
                waterMeters.Add(new  WaterMeter() { WaterMeterId = 50, MeterNumber = "306-842-497", Make = "Lansome",                Model = "9000",     MeterSize = "3/4 Inches" });
    
                string strWaterMeters = string.Empty;
                string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
                string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
            }
    
            private void CreateAccountsTypes()
            {
                List<AccountType> types = new List<AccountType>()
                {
                    new AccountType() { AccountTypeId = 1, TypeCode = "OTH", TypeDecription = "Other" },
                    new AccountType() { AccountTypeId = 3, TypeCode = "RES", TypeDecription = "Residential Household" },
                    new AccountType() { AccountTypeId = 2, TypeCode = "BUS", TypeDecription = "General Business, Commercial, Industrial" },
                    new AccountType() { AccountTypeId = 5, TypeCode = "UUO", TypeDecription = "Unidentified or Unclassified Type of Organization" },
                    new AccountType() { AccountTypeId = 4, TypeCode = "SGO", TypeDecription = "Social/Government/Non-Profit Organization, Institutional" },
                    new AccountType() { AccountTypeId = 6, TypeCode = "WAT", TypeDecription = "Water Intensive Business (Agricultural, Laudromat, Hair Salon, Restaurant, etc" }
                };
    
                string strAccountsTypes       = string.Empty;
                string fileAccountsTypes      = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented         = true;
    
                FileInfo fiAccountsTypes      = new FileInfo(fileAccountsTypes);
                string jsAccountsTypes        = JsonSerializer.Serialize(types, typeof(List<AccountType>), options);
                File.WriteAllText(fiAccountsTypes.FullName, jsAccountsTypes);
            }
    
            public WaterDistribution()
            {
                InitializeComponent();
    
                // CreateWaterMeters();
                // CreateAccountsTypes();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"C:\Stellar Water Point2");
            }
    
            private void btnWaterBills_Click(object sender, EventArgs e)
            {
                WaterBills.Central central = new WaterBills.Central();
    
                central.Show();
            }
    
            private void btnCustomers_Click(object sender, EventArgs e)
            {
                Customers.Central central = new Customers.Central();
    
                central.Show();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.Show();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

A New Water Bill

A water is probably the most important aspect of water distribution. We will provide a form that allows an employee to register the information necessary for water consumption. Then we will perform some operations. Finally, we will present the amount the consumer should pay and when.

Practical Learning: Processing a Water Bill

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. Set the name to 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
   Label		Water Bill Id:&
   TextBox			txtWaterBillId
   Button		Save Water Bill	btnSaveWaterBill
   Button		&Close	btnClose

   Form Properties

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Stellar Water Point - Water Bill Processing
   StartPosition	CenterScreen
   MaximizeBox	False
   MinimizeBox	False

5. Double-click an unoccupied area of the form to generate its Load event
6. Implement the event as follows:

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterMeters
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void Create_Load(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               List<WaterBill> waterBills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               int waterBillId = 0;
   
               if (fiWaterBills.Exists == true)
               {
   
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       waterBills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       foreach (WaterBill wm in waterBills)
                       {
                           waterBillId = wm.WaterBillId;
                       }
                   }
               }
   
               txtWaterBillId.Text = (waterBillId + 1).ToString();
           }
       }
   }

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterBills
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strAccountNumber = mtbAccountNumber.Text.Replace("-", "").Trim();
   
               if (string.IsNullOrEmpty(strAccountNumber))
               {
                   MsgBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.");
                   return;
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string strAccountsTypes = string.Empty;
               List<AccountType> accountsTypes = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           
                           TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                           strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                           accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
                           
                           foreach (AccountType at in accountsTypes)
                           {
                               if (client.AccountType == at.TypeCode)
                               {
                                   txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                               }
                           }
   
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
   
                       foreach (WaterMeter meter in meters)
                       {
                           txtMeterDetails.Text = meter.WaterMeterId.ToString() + " - " +
                                                  meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter 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.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint21.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();
            }
        }
    }

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

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.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();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0, counterEnd = 0;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MsgBox.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)
                {
                    MsgBox.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 Save Water Bill button
14. Return to the form and double-click the Close button to generate its Click event
15. Implement the events as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MsgBox.Show("You must type a valid account number of a customer, " +
                                    "and then click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
                        foreach (Customer client in customers)
                        {
                            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)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
    
                        foreach (WaterMeter meter in meters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter 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 = 0, counterEnd = 0;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MsgBox.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)
                {
                    MsgBox.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))
                {
                    MsgBox.Show("You must type a (unique) bill number for the " +
                                    "water bill you are processing.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MsgBox.Show("You must specify the account number of the customer " +
                                    "whose water bill you are preparing.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills      = string.Empty;
                List<WaterBill> bills     = new List<WaterBill>();
                string fileWaterBills     = @"C:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills     = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists   == true)
                {
                    strWaterBills         = File.ReadAllText(fiWaterBills.FullName);
                    bills                 = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
                }
    
                WaterBill bill            = new()
                {
                    BillNumber            = int.Parse(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);
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                string jsWaterBills = JsonSerializer.Serialize(bills, typeof(List<WaterBill>), options);
                File.WriteAllText(fiWaterBills.FullName, jsWaterBills);
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

16. In the Solution Explorer, below the WaterBills folder, double-click Central.cs
17. From the Toolbox, add a button to the form below the list view
18. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwWaterBills	No Change
    Button		btnProcessWaterBill	&Process Water Bill...

19. On the Central form, double-click the Process Water Bill button
20. Implement the event as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint21.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
        }
    }

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

    

22. On the Water Distribution form, click the Water Bills button:

    

23. On the Water Bills form, click the Create Water Bill button:

    

24. 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

    

25. Close the forms and return to your programming environment

Water Bill Details

Sometimes, an employee just wants to view the information that is related to a water bill. We will create a form to make it possible.

Practical Learning: Showing a Water Bill

1. To create a form, in the Solution Explorer, right-click WaterBills -> 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	Enabled
   Label		&Water Bill #:
   TextBox			txtBillNumber
   Button		&Find Water Bill	btnFindWaterBill
   GroupBox		Customer Information
   Label		&Account #:
   TextBox			txtAccountNumber	False
   Label		Account Name:
   TextBox			txtAccountName	False
   Label		Account Type:
   TextBox			txtAccountType
   Label		Address:		False
   TextBox			txtAddress	False
   TextBox			txtCity
   TextBox			txtCounty	False
   TextBox			txtState	False
   TextBox			txtZIPCode	False
   Label		_______________________________
   Label		Meter Details:
   TextBox			txtMeterDetails	False
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Text Box			txtMeterReadingStartDate	False
   Label		Meter Reading &End Date:
   Text Box			txtMeterReadingEndDate	False
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart	False
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd	False
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays	False
   Label		Total HCF:
   TextBox			txtTotalHCF	False
   Label		Total Gallons:
   TextBox			txtTotalGallons	False
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption	False
   Label		Second Tier:
   TextBox			txtSecondTierConsumption	False
   Label		Last Tier:
   TextBox			txtLastTierConsumption	False
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges	False
   Label		Sewer Charges:
   TextBox			txtSewerCharges	False
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges	False
   Label		Service Charges:
   TextBox			txtServiceCharges	False
   Label		Total Charges:
   TextBox			txtTotalCharges	False
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes	False
   Label		State Taxes:
   TextBox			txtStateTaxes	False
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate	False
   Label		Amount Due:
   TextBox			txtAmountDue	False
   Label		Late Payment Due Date:
   Text Box			txtLatePaymentDueDate	False
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Label		Water Bill Id:
   TextBox			txtWaterBillId	False
   Button		&Close	btnClose

   Form Properties

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Stellar Water Point - Water Bill Details
   StartPosition	CenterScreen
   MaximizeBox	False
   MinimizeBox	False

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterBills
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               string strAccountsTypes = string.Empty;
               List<AccountType> accountsTypes = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           txtWaterBillId.Text = bill.WaterBillId.ToString();
                           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();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               string strAccountType = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == txtAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
   
                           TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                           strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                           accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                           foreach (AccountType at in accountsTypes)
                           {
                               if (client.AccountType == at.TypeCode)
                               {
                                   txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                               }
                           }
   
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterBills
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               // Prepare a bills list to hold the records of water bills
               List<WaterBill> bills = new List<WaterBill>();
               // Specify the file that holds the records of water bills
               string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
   
               // Create a FileInfo object for the records of water bills
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               // Find out whether a file that holds the records of water bills exists already
               if (fiWaterBills.Exists == true)
               {
                   // If that file exists, create a TextReader object to read the file
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       /* Read the contents of the file that holds the water bills.
                        * Store the read text in the strWaterBills variable that was declared. */
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       // Get the water bills and store them in the bills list variable
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           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();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == txtAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           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)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

9. In the Solution Explorer, below the WaterBills folder, double-click Central.cs to open its form
10. From the Toolbox, add a button to the form below the list view and to the right of the New Water Bill button
11. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwWaterBills	No Change
    Button		No Change	No Change
    Button		btnWaterBillDetails	Water Bill &Details...

12. Double-click the Water Bill &Details button
13. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint21.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnViewWaterBill_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
        }
    }

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

    

15. On the Water Distribution form, click the Water Bills button:

    

16. On the Water Bills form, click the View Water Bill button:

    

17. In the Water Bill # text box, type 917829
18. Click the Find Water Bill button:

    

19. Close the forms and return to your programming environment

Water Bill Edition

If some aspect of a water bill changes, we will create a form that an employee can use to update the record.

Practical Learning: Creating a Water Bill Editor

1. In the Solution Explorer, right-click the WaterBills folder -> Add -> Form (Windows Forms...)
2. Set the name of the form to Editor
3. Click Add
4. Using the Properties window, change the size of the new form to match the size of the Process Water Bill form
5. Select everything in the Process Water Bill form and copy it
6. Paste it in Water Bill Editor form
7. Change the design of the Water Bill Editor form as follows (you will add only the controls that are not found in the New Water Bill form):

   

   Control		(Name)	Text
   Button		btnFindWaterBill	&Find Water Bill
   Button		btnUpdateWaterBill	&Update Water Bill

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

   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterBills
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills     = string.Empty;
               List<WaterBill> bills    = new List<WaterBill>();
               string fileWaterBills    = @"C:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills    = new FileInfo(fileWaterBills);
   
               string strAccountsTypes  = string.Empty;
               List<AccountType> accountsTypes = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiWaterBills.Exists  == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills    = File.ReadAllText(fiWaterBills.FullName);
                       bills            = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtWaterBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           txtWaterBillId.Text            = bill.WaterBillId.ToString();
                           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();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               string strAccountType = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
   
                           TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                           strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                           accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                           foreach (AccountType at in accountsTypes)
                           {
                               if (client.AccountType == at.TypeCode)
                               {
                                   txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                               }
                           }
   
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

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

    private void btnFindCustomerAccount_Click(object sender, EventArgs e)
    {
        string strAccountNumber = mtbAccountNumber.Text.Replace("-", "").Trim();
    
        if (string.IsNullOrEmpty(strAccountNumber))
        {
            MsgBox.Show("You must type a valid account number of a customer, " +
                            "and then click the Find Customer Account button.");
            return;
        }
    
        string strCustomers = string.Empty;
        List<Customer> clients = new List<Customer>();
        string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
        FileInfo fiCustomers = new FileInfo(fileCustomers);
    
        string strAccountsTypes = string.Empty;
        List<AccountType> accountsTypes = new List<AccountType>();
        string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
        FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
        string? strMeterNumber = string.Empty;
    
        if (fiCustomers.Exists == true)
        {
            using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
            {
                strCustomers = File.ReadAllText(fiCustomers.FullName);
                clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
                foreach (Customer client in customers)
                {
                    txtAccountName.Text = client.AccountName;
                    strMeterNumber = client.MeterNumber;
    
                    TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                    strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                    accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                    foreach (AccountType at in accountsTypes)
                    {
                        if (client.AccountType == at.TypeCode)
                        {
                            txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                        }
                    }
    
                    txtAddress.Text = client.Address;
                    txtCity.Text = client.City;
                    txtCounty.Text = client.County;
                    txtState.Text = client.State;
                    txtZIPCode.Text = client.ZIPCode;
                }
            }
        }
    
        if (strMeterNumber!.Length > 0)
        {
            string strWaterMeters = string.Empty;
            List<WaterMeter> waterMeters = new List<WaterMeter>();
            string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
            FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
            if (fiWaterMeters.Exists == true)
            {
                strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
    
                foreach (WaterMeter meter in meters)
                {
                    txtMeterDetails.Text = meter.WaterMeterId.ToString() + " - " +
                                           meter.Make + " " +
                                           meter.Model +
                                           " (Meter Size: " + meter.MeterSize + ")";
                }
            }
        }
    }

12. Return to the form and double-click the Meter Reading End Date date time picker control
13. Implement the event as follows:

    private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
    {
        TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
        txtBillingDays.Text = (tsDays.Days + 1).ToString();
    }

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

    private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
    {
        double counterStart = 0, counterEnd = 0;
    
        try
        {
            counterStart = double.Parse(txtCounterReadingStart.Text);
        }
        catch (FormatException feCRStart)
        {
            MsgBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                            "The error produced is: " + feCRStart.Message);
        }
    
        try
        {
            counterEnd = double.Parse(txtCounterReadingEnd.Text);
        }
        catch (FormatException feCREnd)
        {
            MsgBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                            "The error produced is: " + feCREnd.Message);
        }
    
        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");
    }

16. Return to the form and double-click the Update Water Bill button
17. Change the document as follows:

    private void btnUpdateWaterBill_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrEmpty(txtWaterBillNumber.Text))
        {
            MsgBox.Show("You must provide the bill number of the " +
                        "water bill you are trying to update.");
            return;
        }
    
        if (string.IsNullOrEmpty(mtbAccountNumber.Text))
        {
            MsgBox.Show("Please make sure you provide the account number of the customer " +
                        "associated with the water bill you are trying to update.");
            return;
        }
    
        string strWaterBills = string.Empty;
        List<WaterBill> bills = new List<WaterBill>();
        string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
    
        FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
        if (fiWaterBills.Exists == true)
        {
            strWaterBills = File.ReadAllText(fiWaterBills.FullName);
            bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
            WaterBill? bill = bills.Find(invoice => invoice.BillNumber == int.Parse(txtWaterBillNumber.Text));
    
            if (bill is not null)
            {
                bill.WaterBillId = int.Parse(txtWaterBillId.Text);
                bill.BillNumber = int.Parse(txtWaterBillNumber.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);
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                string jsWaterBills = JsonSerializer.Serialize(bills, typeof(List<WaterBill>), options);
                File.WriteAllText(fiWaterBills.FullName, jsWaterBills);
            }
        }
    
        Close();
    }

18. Return to the form and double-click the Close button
19. Change the document as follows:

    private void btnClose_Click(object sender, EventArgs e)
    {
        Close();
    }

20. In the Solution Explorer, below the WaterBills folder, double-click Central.cs
21. From the Toolbox, add a button to the form below the list view and on the right side of the View Water Bill button
22. Change the characteristics of the button as follows:

    

    Control		(Name)	Text
    ListView		lvwWaterBills
    Button		btnNewWaterBill
    Button		btnViewWaterBill
    Button		btnEditWaterBill	&Edit Water Bill...

23. Double-click the Edit Water Bill button
24. Implement the event as follows:

    private void btnWaterBillEditor_Click(object sender, EventArgs e)
    {
        Editor update = new Editor();
    
        update.ShowDialog();
        
        ShowWaterBills();
    }

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

    

26. On the main form of the application, click the Water Bills button:

    

27. Click the Edit Water Bill button:

    

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

    

30. 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

31. Click the Evaluate Water Bill button:

    

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

    

33. Close the forms and return to your programming environment

Water Bill Deletion

If a water bill is useless and must not be kept as a record in the system, an employee must be able to delete it. We will create a form that makes it possible to delete a water bill.

Practical Learning: Deleting a Water Bill Record

1. To create a form, in the Solution Explorer, right-click the WaterBills folder -> Add -> Form (Windows Forms...)
2. Change the file Name to Delete
Click Add Resize the form to have the same size as the Water Bill Details form
3. Select and copy everything in the Water Bill Details form
4. Paste it in the new Water Bill Delete form
5. Change the design of the form as follows (you will add only one button):

   

   Control		(Name)	Text
   Button		btnDeleteWaterBill	&Delete Water Bill

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

   using System.Data;
   using System.Text.Json;
   using StellarWaterPoint2.Models;
   
   namespace StellarWaterPoint2.WaterBills
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               string strAccountsTypes = string.Empty;
               List<AccountType> accountsTypes = new List<AccountType>();
               string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtWaterBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           txtWaterBillId.Text = bill.WaterBillId.ToString();
                           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();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               string strAccountType = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == txtAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
   
                           TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                           strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                           accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                           foreach (AccountType at in accountsTypes)
                           {
                               if (client.AccountType == at.TypeCode)
                               {
                                   txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                               }
                           }
   
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

8. Return to the form and double-click the Delete Water Bill button
9. Return to the form and double-click the Close button
10. Change the document as follows:

    using System.Data;
    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterBills
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                string strWaterBills = string.Empty;
                List<WaterBill> bills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                string strAccountsTypes = string.Empty;
                List<AccountType> accountsTypes = new List<AccountType>();
                string fileAccountsTypes = @"C:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiWaterBills.Exists == true)
                {
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtWaterBillNumber.Text));
    
                        foreach (var bill in selected)
                        {
                            txtWaterBillId.Text = bill.WaterBillId.ToString();
                            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();
                        }
                    }
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                string strAccountType = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = from consumer
                                                          in clients
                                                          where consumer.AccountNumber == txtAccountNumber.Text
                                                          select consumer;
    
                        foreach (Customer client in customers)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
    
                            TextReader trAccountsTypess = new StreamReader(fiAccountsTypes.FullName);
                            strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                            accountsTypes = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                            foreach (AccountType at in accountsTypes)
                            {
                                if (client.AccountType == at.TypeCode)
                                {
                                    txtAccountType.Text = string.Concat(at.TypeCode, " - ", at.TypeDecription);
                                }
                            }
    
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            txtZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"C:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = from measure
                                                         in waterMeters
                                                         where measure.MeterNumber == strMeterNumber
                                                         select measure;
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnDeleteWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtWaterBillNumber.Text))
                {
                    MsgBox.Show("Please provide the bill number of the water bill you want to delete, " +
                                "and then click the Find Water Bill button.");
                    return;
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> waterBills = new List<WaterBill>();
                string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                    waterBills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                    WaterBill bill = waterBills.Find(bl => bl.BillNumber == int.Parse(txtWaterBillNumber.Text))!;
    
                    if (bill is not null)
                    {
                        if (MsgBox.Question("Are you sure you want to delete (or remove) or cancel " +
                                            "this water bill from the system (you cannot undo the action)?") == Answer.Yes)
                        {
                            waterBills.Remove(bill);
    
                            JsonSerializerOptions options = new JsonSerializerOptions();
                            options.WriteIndented = true;
    
                            string jsWaterBills = JsonSerializer.Serialize(waterBills, typeof(List<WaterBill>), options);
                            File.WriteAllText(fiWaterBills.FullName, jsWaterBills);
    
                            MsgBox.Show("The water bill has been deleted (or removed, or cancelled) from our system.");
                        }
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

11. In the Solution Explorer, below the WaterBills folder, double-click Central.cs to open its form
12. From the Toolbox, add two buttons to the form below the list view and to the right of the Edit Water Bill button
13. Change the form design as follows:

    

    Control		(Name)	Text	Other Properties
    ListView		lvwWaterBills		Anchor: Bottom, Top, Bottom, Left, Right
    Button		btnProcessWaterBill	&Process Water Bill...	Anchor: Bottom, Right
    Button		btnViewWaterBill	&View Water Bill...	Anchor: Bottom, Right
    Button		btnEditWaterBill	&Edit Water Bill...	Anchor: Bottom, Right
    Button		btnDeleteWaterBill	&Delete Water Bill...	Anchor: Bottom, Right
    Button		btnClose	&Close	Anchor: Bottom, Right

14. On the form, double-click the Delete Water Bill button
15. Return to the Water Bills - Central form and double-click the Close button
16. Implement the events as follows:

    using System.Text.Json;
    using StellarWaterPoint2.Models;
    
    namespace StellarWaterPoint2.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                // We will need the list of customers to display an account summary in the list view
                // Declare a strCustomers variable that will hold the records from the JSON file
                string strCustomers = string.Empty;
                // Prepare a list to hold the records of customers
                List<Customer> clients = new List<Customer>();
                // Specify the file that holds the records of customers
                string fileCustomers = @"C:\Stellar Water Point2\Customers.json";
    
                // Create a FileInfo object for the records of customers
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                // Check if a file that holds the records of customers was created already
                if (fiCustomers.Exists == true)
                {
                    // If that file exists, create a TextReader object to get those records
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        // Read the records and store them in the strCustomers variable
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        // Use JSON deserialization to get the records of customers
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
                }
    
                // Declare a strWaterBills variable that will hold the records from the JSON file
                string strWaterBills = string.Empty;
                // Prepare a bills list to hold the records of water bills
                List<WaterBill> bills = new List<WaterBill>();
                // Specify the file that holds the records of water bills
                string fileWaterBills = @"C:\Stellar Water Point2\WaterBills.json";
    
                // Create a FileInfo object for the records of water bills
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                // Find out whether a file that holds the records of water bills exists already
                if (fiWaterBills.Exists == true)
                {
                    // If that file exists, create a TextReader object to read the file
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        /* Read the contents of the file that holds the water bills.
                         * Store the read text in the strWaterBills variable that was declared. */
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        // Get the water bills and store them in the bills list variable
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        /* We are about to display the water bills records in the list view.
                         * Before proceeding, first remove any record in the list view. */
                        lvwWaterBills.Items.Clear();
    
                        // Visit each record of the water bills
                        foreach (WaterBill invoice in bills)
                        {
                            /* Prepare a ListViewItem object for each record.
                             * Display the record counter in the first column of this object. */
                            ListViewItem lviWaterBill = new ListViewItem(invoice.WaterBillId.ToString());
    
                            // Display the water bill number of the current record
                            lviWaterBill.SubItems.Add(invoice.BillNumber.ToString());
    
                            /* Refer to the list of records of the customers (that list was prepared earlier).
                             * Use LINQ to get the customer whose account number is 
                             * the same as the account number of the current record. */
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == invoice.AccountNumber);
    
                            // Now that we have located the customer record, display some details about it
                            foreach (Customer cust in customer)
                            {
                                lviWaterBill.SubItems.Add(invoice.AccountNumber + " - " +
                                                          cust.AccountName +
                                                          ", Type: " + cust.AccountType![..3] +
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            /* Continue displaying some other parts of the water bill.
                             * Before there is not enough space for the whole water bill, we display only some values. */
                            lviWaterBill.SubItems.Add(invoice.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(invoice.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(invoice.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(invoice.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(invoice.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(invoice.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(invoice.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new Create();
                
                create.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnWaterBillDetails_Click(object sender, EventArgs e)
            {
                Details details = new Details();
                
                details.ShowDialog();
            }
    
            private void btnWaterBillEditor_Click(object sender, EventArgs e)
            {
                Editor update = new Editor();
    
                update.ShowDialog();
                
                ShowWaterBills();
            }
    
            private void btnDeleteWaterBill_Click(object sender, EventArgs e)
            {
                Delete delete = new Delete();
                
                delete.ShowDialog();
                
                ShowWaterBills();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

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

    

18. On the Stellar Water Point form, click the Water Bills button

    

19. On the Water Bills form, click the Delete Water Bill button

    

20. In the Water Bill # text box, type 917829:

    

21. Click Find Water Bill

    

22. Click Delete Water Bill:

    

23. Read the message in the message box and click Yes:

    

24. Read the message in the message box and click OK:

    

25. Close the forms and return to your programming environment
26. Close Microsoft Visual Studio

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