XPath Sample Application: Bethesda Car Rental

	XPath Sample Application: Bethesda Car Rental

Introduction

The XPath language provides flexible techniques to locate a node within an XML document. The XPath language is standardized by the W3C organization. The MSXML library and the .NET Framework present Microsoft implementation of the XPath language.

Practical Learning: Introducing Dictionary Collections

Start Microsoft Visual Studio
Create a new Windows Application named BethesdaCarRental2
To add a new form to the project, in the Solution Explorer, right-click BethesdaCarRental1 -> Add -> Windows Form...
Set the Name to RentalRates and press Enter

Add a ListView to the form and create its Columns as follows:

(Name)	Text	TextAlign	Width
colCategory	Category		90
colDaily	Daily	Right
colWeekly	Weekly	Right
colMonthly	Monthly	Right
colWeekend	Weekend	Right

Create its Items as follows:

ListViewItem	SubItems	SubItems	SubItems	SubItems
	Text	Text	Text	Text
Economy	35.95	32.75	28.95	24.95
Compact	39.95	35.75	32.95	28.95
Standard	45.95	39.75	35.95	32.95
Full Size	49.95	42.75	38.95	35.95
Mini Van	55.95	50.75	45.95	42.95
SUV	55.95	50.75	45.95	42.95
Truck	42.75	38.75	35.95	32.95
Van	69.95	62.75	55.95	52.95

Complete the design of the form as follows:
To add another form to the application, in the Solution Explorer, right- click BethesdaCarRental1 -> Add -> Windows Form...
Set the Name to EmployeeEditor and click Add

Design the form as follows:

Control	(Name)	Text	Properties
Label		&Employee #:
TextBox	txtEmployeeNumber		Modifiers: public
Label		First Name:
TextBox	txtFirstName		Modifiers: public
Label		Last Name:
TextBox	txtLastName		Modifiers: public
Label		Title:
TextBox	txtTitle		Modifiers: public
Button	btnOK	OK	DialogResult: OK
Button	btnCancel	Cancel	DialogResult: Cancel
Form			AcceptButton: btnOK CancelButton: btnCancel FormBorderStyle: FixedDialog MaximizeBox: False MinimizeBox: False ShowInTaskbar: False

To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental1 -> Add -> Windows Form...
Set the Name to Employees and click Add
From the Toolbox, add a ListView to the form

While the new list view is still selected, in the Properties window, click the ellipsis button of the Columns field and create the columns as follows:

(Name)	Text	Width
colEmployeeNumber	Empl #	45
colFirstName	First Name	65
colLastName	Last Name	65
colTitle	Title	120

Design the form as follows:

Control	(Name)	Text	Other Properties
ListView	lvwEmployees		Anchor: Top, Bottom, Left, Right FullRowSelect: True GridLines: True View: Details
Button	btnNewEmployee	New &Employee...
Button	btnClose	&Close

Double-click the New Employee button and change the document as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Xml;

namespace BethesdaCarRental2
{
    public partial class Employees : Form
    {
        public Employees()
        {
            InitializeComponent();
        }

        internal void ShowEmployees()
        {
        }

        private void btnNewEmployee_Click(object sender, EventArgs e)
        {
            XmlDocument xdEmployees = new XmlDocument();
            EmployeeEditor editor = new EmployeeEditor();
            string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Employees.xml";

            if (editor.ShowDialog() == DialogResult.OK)
            {
                if (string.IsNullOrEmpty(editor.txtEmployeeNumber.Text))
                {
                    MessageBox.Show("You must specify the employee number.",
                                    "Bethesda Car Rental",
                                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                    return;
                }

                if (!File.Exists(strFileName))
                {
                    xdEmployees.LoadXml("<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
                                        "<Employees></Employees>");
                    xdEmployees.Save(strFileName);
                }

                xdEmployees.Load(strFileName);

                // Create an element named Employee
                XmlElement elmXML = xdEmployees.CreateElement("Employee");
                // Create the XML code of the child element of Employee
                elmXML.InnerXml = "<EmployeeNumber>" + editor.txtEmployeeNumber.Text + "</EmployeeNumber>" +
                                  "<FirstName>" + editor.txtFirstName.Text + "</FirstName>" +
                                  "<LastName>" + editor.txtLastName.Text + "</LastName>" +
                                  "<Title>" + editor.txtTitle.Text + "</Title>";
                // Append the new element as a child of employees
                xdEmployees.DocumentElement.AppendChild(elmXML);

                // Save the XML file
                xdEmployees.Save(strFileName);
                // Since the content of the XML file has just been changed,
                // re-display the list of employees
                ShowEmployees();
            }
        }
    }
}

To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental1 -> Add -> Windows Forms
Set the Name to VehicleEditor and click Add

Design the form as follows:

Control	(Name)	Text	Other Properties
Label		Tag Number:
TextBox	txtTagNumber
Label		Make:
TextBox	txtMake
Label		Model:
TextBox	txtModel
Label		Doors
TextBox	txtDoors
Label		Passengers:
TextBox	txtPassengers
Label		Condition:
ComboBox	cbxCondition		Items: Good Other Excellent Driveable Needs Repair
Label		Category:
ComboBox	cbxCategories		Items: SUV Truck Full Size Mini Van Compact Standard Economy Passenger Van
Label		Availability
ComboBox	cbxAvailabilities		Items: Rented Available Being Serviced
PictureBox	pbxVehicle		SizeMode: Zoom
Button	btnSelectPicture	&Select Vehicle Picture...
Label	lblPictureName	Picture Name
Button	btnSubmit	Submit
Button	btnClose	Close	DialogResult: Cancel
OpenFileDialog	(Name): dlgOpen Title: Select Item Picture DefaultExt: jpg Filter: JPEG Files (.jpg,.jpeg)\|.jpg\|GIF Files (.gif)\|.gif\|Bitmap Files (.bmp)\|.bmp\|PNG Files (.png)\|*.png
Form			FormBorderStyle: FixedDialog MaximizeBox: False MinimizeBox: False ShowInTaskbar: False

Double-click an unoccupied area of the form and change the document as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Xml;

namespace BethesdaCarRental2
{
    public partial class VehicleEditor : Form
    {
        public VehicleEditor()
        {
            InitializeComponent();
        }

        private void VehicleEditor_Load(object sender, EventArgs e)
        {
            pbxVehicle.Image = Image.FromFile(@"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicle1.jpg");
            lblPictureName.Text = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicle1.jpg";
        }
    }
}

Return to the Vehicle Editor form and double-click the Select Vehicle Picture button and implement its event as follows:

private void btnSelectPicture_Click(object sender, EventArgs e)
{
    if (dlgPicture.ShowDialog() == DialogResult.OK)
    {
        lblPictureName.Text = dlgPicture.FileName;
        pbxVehicle.Image = Image.FromFile(lblPictureName.Text);
    }
}

Return to the Vehicle Editor form and double-click the Submit button

Implement the event as follows:

private void btnSubmit_Click(object sender, EventArgs e)
{
    XmlDocument xdVehicles = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicles.xml";


    if (string.IsNullOrEmpty(txtTagNumber.Text))
    {
        MessageBox.Show("You must specify the tag number.",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
        return;
    }

    if (!File.Exists(strFileName))
    {
        xdVehicles.LoadXml("<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
                            "<Vehicles></Vehicles>");
        xdVehicles.Save(strFileName);
    }

    xdVehicles.Load(strFileName);

    XmlElement elmXML = xdVehicles.CreateElement("Vehicle");
    elmXML.InnerXml = "<TagNumber>" + txtTagNumber.Text + "</TagNumber>" +
                      "<Make>" + txtMake.Text + "</Make>" +
                      "<Model>" + txtModel.Text + "</Model>" +
                      "<Doors>" + txtDoors.Text + "</Doors>" +
                      "<Passengers>" + txtPassengers.Text + "</Passengers>" +
                      "<Condition>" + cbxConditions.Text + "</Condition>" +
                      "<Category>" + cbxCategories.Text + "</Category>" +
                      "<Availability>" + cbxAvailabilities.Text + "</Availability>" +
                      "<PictureFile>" + lblPictureName.Text + "</PictureFile>";
    xdVehicles.DocumentElement.AppendChild(elmXML);

    // Save the XML file
    xdVehicles.Save(strFileName);
    Close();
}

Return to the Vehicle Editor form and double-click the Close button

Implement the event as follows:

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

To add a new form, on the main menu, click PROJECT -> Add Windows Form ...
Set the Name to Vehicles and click Add
Set the Size to around 765, 524
Press Ctrl + V to paste dsVehicles
From the Containers section of the Toolbox, click Panel and click the form
Set its Dock property to Top
From the Containers section of the Toolbox, click Panel and click the form
Set its Dock property to Bottom
From the Containers section of the Toolbox, click SplitContainer and click the middle-unoccupied area of the form
From the Containers section of the Toolbox, click SplitContainer and click the right panel (Panel2) of the form
In the Properties window, set the Oriantation to Horizontal

Complete the design of the form as follows:

Control

(Name)

Text

Other Properties

Label

Bethesda Car Rental - Vehicles Inventory

ForeColor: Blue

Label

________________

Anchor: Left, Right
AutoSize: False
BackColor: Maroon
BorderStyle: FixedSingle

TreeView

tvwVehicles

Dock: Fill
FullRowSelect: True
GridLines: True
View: Details

ListView

lvwVehicles

Dock: Fill

(Name)	Text	TextAlign	Width
colTagNumber	Tag #		55
colMake	Make		70
colModel	Model		75
colDoors	Doors	Right	40
colPassengers	Passengers	Right	68
colCondition	Condition
colCategory	Category		70
colAvailability	Availability		85

PictureBox

pbxVehicle

Dock: Fill
SizeMode: Zoom

Button

btnNewVehicle

New Vehicle...

Button

btnClose

Double-click the New Vehicle button and change the document as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Xml;

namespace BethesdaCarRental2
{
    public partial class Vehicles : Form
    {
        public Vehicles()
        {
            InitializeComponent();
        }

        private void ShowVehicles()
        {            
        }

        private void btnNewVehicle_Click(object sender, EventArgs e)
        {
            VehicleEditor editor = new VehicleEditor();
            editor.Text = "Bethesda Car Rental - New Vehicle";
            editor.ShowDialog();
            ShowVehicles();
        }
    }
}

Return to the Vehicles form and click the list view
On the Properties window, click the Events button and double-click ItemSelectionChanged

Implement the event as follows:

private void lvwVehicles_ItemSelectionChanged(object sender, ListViewItemSelectionChangedEventArgs e)
{
    string strPictureFile = e.Item.SubItems[8].Text;
    
    if (File.Exists(strPictureFile))
        pbxVehicle.Image = Image.FromFile(strPictureFile);
    else
        pbxVehicle.Image = Image.FromFile(@"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicle1.jpg");
}

To add a new form to the project, in the Solution Explorer, right-click BethesdaCarRenat1 -> Add -> Windows Form...
Set the Name to NewRentalOrder and press Enter
From the Printing section of the Toolbox, click PrintDocument and click the form
In the Properties window, set its (Name) to docPrint and press Enter
From the Printing section of the Toolbox, click PrintDialog and click the form
In the Properties window, change its Name to dlgPrint
Still in the Properties windows, set its Document property to docPrint
From the Printing section of the Toolbox, click PrintPreviewDialog and click the form
In the Properties window, change its (Name) to dlgPrintPreview
Still in the Properties windows, set its Document property to docPrint

Set the dimensions to those of the Update Rental Order form, then copy all controls from the Update Rental Order form and paste them on the New Rental Order form.
Design the form as follows:

Control	(Name)	Text	Other Properties
Label		Processed By:	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Order Timing	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Employee #:
TextBox	txtEmployeeNumber
TextBox	txtEmployeeName
Label		Date Processed:
TextBox	dtpDateProcessed
Label		Processed For	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Rent Start Date:
DateTimePicker	dtpRentStartDate
Label		First Name:
TextBox	txtCustomerFirstName
Label		Last Name:
TextBox	txtCustomerLastName
Label		Rent End Date:
DateTimePicker	dtpRentEndDate
Label		Address:
TextBox	txtCustomerAddress
Label		Total Days:
TextBox	txtTotalDays	1	TextAlign: Right
Label		City:
TextBox	txtCustomerCity
Label		State:
Label	Order Evaluation		AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
ComboBox	cbxCustomerStates		DropDownStyle: DropDownList Sorted: True Items: AB, AL, AK, AZ, AR, BC, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, MT, NB, NE, NV, NH, NJ, NL, NM, NS, NY, NC, ND, OH, OK, ON, OR, PA, PE, QC, RI, SC, SD, SK, TN, TX, UT, VT, VA, WA, WV, WI, WY
Label		ZIP/Postal Code:
TextBox	txtCustomerZIPCode
Label		Rate Applied:
TextBox	txtRateApplied	0.00	TextAlign: Right
Button	btnRentalRates	Rental Rates
Label	Vehicle Selected		AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Sub-Total:
TextBox	txtSubTotal	0.00	TextAlign: Right
Label		Tag Number:
TextBox	txtTagNumber
Label		Condition:
ComboBox	cbxVehicleConditions		Sorted: True Items: Bad Good Other Excellent Driveable Needs Repair
Label		Tax Rate:
TextBox	txtTaxRate	7.75	TextAlign: Right
Label		%
Label		Make:
TextBox	txtMake
Label		Model:
TextBox	txtModel
Label		Tax Amount:
TextBox	txtTaxAmount	0.00	TextAlign: Right
Button	Print...	btnPrint
Label		Mileage Start:
TextBox	txtMileageStart		TextAlign: Right
Label		Tank Level:
ComboBox	cbxTanksLevels		Empty 1/4 Empty Half Tank 3/4 Full Full
Label		Order Total:
TextBox	txtOrderTotal	0.00	TextAlign: Right
Button	btnPrintPreview	Print Preview...
Label		Mileage End:
TextBox	txtMileageEnd		TextAlign: Right
Label		Mileage Total:
TextBox	txtMileageTotal		TextAlign: Right
Label	Order Status
ComboBox		cbxOrderStatus	Items: Order Reserved Vehicle With Customer Rental Order Completed
Label		Notes:
TextBox	txtNotes		Multiline: True ScrollBars: Vertical
Label	Receipt #:
TextBox		txtReceiptNumber
Button	btnOpen	Open
Button	btnUpdateRentalOrder	Update Rental Order
Button	Close	btnClose

On the New Rental Order form, double-click the Rent Start Date date time picker control

Implement the event as follows:

private void dtpRentStartDate_ValueChanged(object sender, EventArgs e)
{
    dtpRentEndDate.Value = dtpRentStartDate.Value;
}

Return to the New Rental Order form and double-click the Rental Rates button

Implement its event as follows:

private void btnRentalRates_Click(object sender, EventArgs e)
{
    RentalRates rates = new RentalRates();
    rates.Show();
}

Return to the New Rental Order form and, under the form, double-click docPrint

Implement its event as follows:

private void docPrint_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawLine(new Pen(Color.Black, 2), 80, 90, 750, 90);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 80, 93, 750, 93);

    string strDisplay = "Bethesda Car Rental";
    System.Drawing.Font fntBoldString = new Font("Times New Roman", 28, FontStyle.Bold);
    e.Graphics.DrawString(strDisplay, fntBoldString, Brushes.Black, 240, 100);

    strDisplay = "Vehicle Rental Order";
    System.Drawing.Font fntRegularString = new System.Drawing.Font("Times New Roman", 22, FontStyle.Regular);
    e.Graphics.DrawString(strDisplay, fntRegularString, Brushes.Black, 280, 150);

    e.Graphics.DrawLine(new Pen(Color.Black, 1), 80, 187, 750, 187);
    e.Graphics.DrawLine(new Pen(Color.Black, 2), 80, 190, 750, 190);

    fntBoldString = new Font("Times New Roman", 12, FontStyle.Bold);
    fntRegularString = new System.Drawing.Font("Times New Roman", 12, FontStyle.Regular);

    e.Graphics.DrawString("Receipt #:  ", fntBoldString, Brushes.Black, 100, 220);
    e.Graphics.DrawString(txtReceiptNumber.Text, fntRegularString, Brushes.Black, 260, 220);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 240, 380, 240);

    e.Graphics.DrawString("Processed By:  ", fntBoldString, Brushes.Black, 420, 220);
    e.Graphics.DrawString(txtEmployeeName.Text, fntRegularString, Brushes.Black, 550, 220);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 240, 720, 240);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 260, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 260, 620, 20));

    e.Graphics.DrawString("Customer", fntBoldString, Brushes.White, 100, 260);

    e.Graphics.DrawString("First Name: ", fntBoldString, Brushes.Black, 100, 300);
    e.Graphics.DrawString(txtCustomerFirstName.Text, fntBoldString, Brushes.Black, 260, 300);
    e.Graphics.DrawString("Last Name: ", fntBoldString, Brushes.Black, 420, 300);
    e.Graphics.DrawString(txtCustomerLastName.Text, fntBoldString, Brushes.Black, 540, 300);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 320, 720, 320);

    e.Graphics.DrawString("Address: ", fntBoldString, Brushes.Black, 100, 330);
    e.Graphics.DrawString(txtCustomerAddress.Text, fntRegularString, Brushes.Black, 260, 330);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 350, 720, 350);

    strDisplay = txtCustomerCity.Text + " " + cbxCustomerStates.Text + " " + txtCustomerZIPCode.Text;
    e.Graphics.DrawString(strDisplay, fntRegularString, Brushes.Black, 260, 360);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 260, 380, 720, 380);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 410, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 410, 620, 20));

    e.Graphics.DrawString("Car Information", fntBoldString, Brushes.White, 100, 410);

    e.Graphics.DrawString("Tag #: ", fntBoldString, Brushes.Black, 100, 450);
    e.Graphics.DrawString(txtTagNumber.Text, fntRegularString, Brushes.Black, 260, 450);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 470, 380, 470);

    e.Graphics.DrawString("Condition: ", fntBoldString, Brushes.Black, 420, 450);
    e.Graphics.DrawString(cbxVehiclesConditions.Text, fntRegularString, Brushes.Black, 530, 450); // ?
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 470, 720, 470);

    e.Graphics.DrawString("Make: ", fntBoldString, Brushes.Black, 100, 480);
    e.Graphics.DrawString(txtMake.Text, fntRegularString, Brushes.Black, 260, 480);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 500, 380, 500);

    e.Graphics.DrawString("Model: ", fntBoldString, Brushes.Black, 420, 480);
    e.Graphics.DrawString(txtModel.Text, fntRegularString, Brushes.Black, 530, 480);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 500, 720, 500);

    e.Graphics.DrawString("Vehicle Condition: ", fntBoldString, Brushes.Black, 100, 510);
    e.Graphics.DrawString(cbxVehiclesConditions.Text, fntRegularString, Brushes.Black, 260, 510);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 530, 380, 530);

    e.Graphics.DrawString("Tank Level: ", fntBoldString, Brushes.Black, 420, 510);
    e.Graphics.DrawString(cbxTanksLevels.Text, fntRegularString, Brushes.Black, 530, 510);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 530, 720, 530);

    e.Graphics.DrawString("Mileage Start:", fntBoldString, Brushes.Black, 100, 540);
    e.Graphics.DrawString(txtMileageStart.Text, fntRegularString, Brushes.Black, 260, 540);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 560, 380, 560);

    e.Graphics.DrawString("Mileage End:", fntBoldString, Brushes.Black, 420, 540);
    e.Graphics.DrawString(txtMileageEnd.Text, fntRegularString, Brushes.Black, 530, 540);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 560, 720, 560);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 590, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 590, 620, 20));

    e.Graphics.DrawString("Order Timing Information", fntBoldString, Brushes.White, 100, 590);

    e.Graphics.DrawString("Start Date:", fntBoldString, Brushes.Black, 100, 620);
    e.Graphics.DrawString(dtpRentStartDate.Value.ToString("D"), fntRegularString, Brushes.Black, 260, 620);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 640, 720, 640);

    e.Graphics.DrawString("End Date:", fntBoldString, Brushes.Black, 100, 650);
    e.Graphics.DrawString(dtpRentEndDate.Value.ToString("D"), fntRegularString, Brushes.Black, 260, 650);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 670, 520, 670);

    e.Graphics.DrawString("Total Days:", fntBoldString, Brushes.Black, 550, 650);
    e.Graphics.DrawString(txtTotalDays.Text, fntRegularString, Brushes.Black, 640, 650);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 550, 670, 720, 670);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 700, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 700, 620, 20));

    e.Graphics.DrawString("Order Evaluation", fntBoldString, Brushes.White, 100, 700);

    StringFormat fmtString = new StringFormat();
    fmtString.Alignment = StringAlignment.Far;

    e.Graphics.DrawString("Rate Applied:", fntBoldString, Brushes.Black, 100, 740);
    e.Graphics.DrawString(txtRateApplied.Text, fntRegularString, Brushes.Black, 300, 740, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 760, 380, 760);

    e.Graphics.DrawString("Tax Rate:", fntBoldString, Brushes.Black, 420, 740);
    e.Graphics.DrawString(txtTaxRate.Text, fntRegularString, Brushes.Black, 640, 740, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 760, 720, 760);

    e.Graphics.DrawString("Sub-Total:", fntBoldString, Brushes.Black, 100, 770);
    e.Graphics.DrawString(txtSubTotal.Text, fntRegularString, Brushes.Black, 300, 770, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 790, 380, 790);

    e.Graphics.DrawString("Tax Amount:", fntBoldString, Brushes.Black, 420, 770);
    e.Graphics.DrawString(txtTaxAmount.Text, fntRegularString, Brushes.Black, 640, 770, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 790, 720, 790);

    e.Graphics.DrawString("Order Total:", fntBoldString, Brushes.Black, 420, 800);
    e.Graphics.DrawString(txtOrderTotal.Text, fntRegularString, Brushes.Black, 640, 800, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 820, 720, 820);
}

Return to the New Rental Order form and double-click the Print button

Implement the event as follows:

private void btnPrint_Click(object sender, EventArgs e)
{
    if (dlgPrint.ShowDialog() == DialogResult.OK)
        docPrint.Print();
}

Return to the New Rental Order form and double-click the Print Preview button

Implement the event as follows:

private void btnPrintPreview_Click(object sender, EventArgs e)
{
    dlgPrintPreview.ShowDialog();
}

Return to the New Rental Order form and double-click the Save Rental Order button

Implement the event as follows:

private void btnSaveRentalOrder_Click(object sender, EventArgs e)
{
    XmlDocument xdRentalOrders = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\RentalOrders.xml";

    if (string.IsNullOrEmpty( txtReceiptNumber.Text))
    {
        MessageBox.Show("You must enter a receipt number.",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
        return;
    }

    if (!File.Exists(strFileName))
    {
        xdRentalOrders.LoadXml("<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
                               "<RentalOrders></RentalOrders>");
        xdRentalOrders.Save(strFileName);
    }

    xdRentalOrders.Load(strFileName);

    XmlElement xeRentalOrder = xdRentalOrders.CreateElement("RentalOrder");
    xeRentalOrder.InnerXml = "<ReceiptNumber>" + txtReceiptNumber.Text + "</ReceiptNumber>" +
                             "<DateProcessed>" + dtpDateProcessed.Value + "</DateProcessed>" +
                             "<EmployeeNumber>" + txtEmployeeNumber.Text + "</EmployeeNumber>" +
                             "<CustomerFirstName>" + txtCustomerFirstName.Text + "</CustomerFirstName>" +
                             "<CustomerLastName>" + txtCustomerLastName.Text + "</CustomerLastName>" +
                             "<CustomerAddress>" + txtCustomerAddress.Text + "</CustomerAddress>" +
                             "<CustomerCity>" + txtCustomerCity.Text + "</CustomerCity>" +
                             "<CustomerState>" + cbxCustomerStates.Text + "</CustomerState>" +
                             "<CustomerZIPCode>" + txtCustomerZIPCode.Text + "</CustomerZIPCode>" +
                             "<VehicleTagNumber>" + txtTagNumber.Text +  "</VehicleTagNumber>" +
                             "<VehicleCondition>" + cbxVehiclesConditions.Text +  "</VehicleCondition>" +
                             "<TankLevel>" + cbxTanksLevels.Text +  "</TankLevel>" +
                             "<MileageStart>" + txtMileageStart.Text +  "</MileageStart>" +
                             "<MileageEnd>" + txtMileageStart.Text + "</MileageEnd>" +
                             "<MileageTotal>0</MileageTotal>" +
                             "<RentStartDate>" + dtpRentStartDate.Value + "</RentStartDate>" +
                             "<RentEndDate>" + dtpRentStartDate.Value + "</RentEndDate>" +
                             "<TotalDays>1</TotalDays>" +
                             "<RateApplied>" + txtRateApplied.Text +  "</RateApplied>" +
                             "<SubTotal>0</SubTotal>" +
                             "<TaxRate>" + txtTaxRate.Text +  "</TaxRate>" +
                             "<TaxAmount>0</TaxAmount>" +
                             "<OrderTotal>0</OrderTotal>" +
                             "<OrderStatus>" + cbxOrdersStatus.Text +  "</OrderStatus>" +
                             "<Notes>" + txtNotes.Text +  "</Notes>";
    xdRentalOrders.DocumentElement.AppendChild(xeRentalOrder);

    // Save the XML file
    xdRentalOrders.Save(strFileName);
    Close();
}

To add a new form to the project, in the Solution Explorer, right-click BethesdaCarRenat1 -> Add -> Windows Form...
Set the Name to UpdateRentalOrder and press Enter
From the Printing section of the Toolbox, click PrintDocument and click the form
In the Properties window, set its (Name) to docPrint and press Enter
From the Printing section of the Toolbox, click PrintDialog and click the form
In the Properties window, change its Name to dlgPrint
Still in the Properties windows, set its Document property to docPrint
From the Printing section of the Toolbox, click PrintPreviewDialog and click the form
In the Properties window, change its (Name) to dlgPrintPreview
Still in the Properties windows, set its Document property to docPrint

Design the form as follows:

Control	(Name)	Text	Other Properties
Label		Processed By:	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Order Timing	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Employee #:
TextBox	txtEmployeeNumber
TextBox	txtEmployeeName
Label		Date Processed:
TextBox	dtpDateProcessed
Label		Processed For	AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Rent Start Date:
DateTimePicker	dtpRentStartDate
Label		First Name:
TextBox	txtCustomerFirstName
Label		Last Name:
TextBox	txtCustomerLastName
Label		Rent End Date:
DateTimePicker	dtpRentEndDate
Label		Address:
TextBox	txtCustomerAddress
Label		Total Days:
TextBox	txtTotalDays	1	TextAlign: Right
Label		City:
TextBox	txtCustomerCity
Label		State:
Label	Order Evaluation		AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
ComboBox	cbxCustomerStates		DropDownStyle: DropDownList Sorted: True Items: AB, AL, AK, AZ, AR, BC, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, MT, NB, NE, NV, NH, NJ, NL, NM, NS, NY, NC, ND, OH, OK, ON, OR, PA, PE, QC, RI, SC, SD, SK, TN, TX, UT, VT, VA, WA, WV, WI, WY
Label		ZIP/Postal Code:
TextBox	txtCustomerZIPCode
Label		Rate Applied:
TextBox	txtRateApplied	0.00	TextAlign: Right
Button	btnRentalRates	Rental Rates
Label	Vehicle Selected		AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft
Label		Sub-Total:
TextBox	txtSubTotal	0.00	TextAlign: Right
Button	btnCalculate	Calculate
Label		Tag Number:
TextBox	txtTagNumber
Label		Condition:
ComboBox	cbxVehicleConditions		Sorted: True Items: Bad Good Other Excellent Driveable Needs Repair
Label		Tax Rate:
TextBox	txtTaxRate	7.75	TextAlign: Right
Label		%
Label		Make:
TextBox	txtMake
Label		Model:
TextBox	txtModel
Label		Tax Amount:
TextBox	txtTaxAmount	0.00	TextAlign: Right
Button	btnPrint	Print...
Label		Mileage Start:
TextBox	txtMileageStart		TextAlign: Right
Label		Tank Level:
ComboBox	cbxTanksLevels		Empty 1/4 Empty Half Tank 3/4 Full Full
Label		Order Total:
TextBox	txtOrderTotal	0.00	TextAlign: Right
Button	btnPrintPreview	Print Preview...
Label		Mileage End:
TextBox	txtMileageEnd		TextAlign: Right
Label		Mileage Total:
TextBox	txtMileageTotal		TextAlign: Right
Label		Order Status
ComboBox		cbxOrderStatus	Items: Order Reserved Vehicle With Customer Rental Order Completed
Label		Notes:
TextBox	txtNotes		Multiline: True ScrollBars: Vertical
Label		Receipt #:
TextBox	txtReceiptNumber
Button	btnOpen	Open
Button	btnUpdateRentalOrder	Update Rental Order
Button	btnClose	Close

On the Update Rental Order form, click the Mileage End text box
On the Properties window, click the Events button and double-click Leave

Implement the event as follows:

private void txtMileageEnd_Leave(object sender, EventArgs e)
{
    int mileageStart = 0, mileageEnd = 0;

    try
    {
        mileageStart = int.Parse(txtMileageStart.Text);
    }
    catch (FormatException fe)
    {
        MessageBox.Show("There was a problem with the mileage start value.\n" +
                        "Please report the error as\n" +
                        fe.Message,
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    try
    {
        mileageEnd = int.Parse(txtMileageEnd.Text);
    }
    catch (FormatException fe)
    {
        MessageBox.Show("There was a problem with the mileage end value.\n" +
                        "Please report the error as\n" +
                        fe.Message,
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    txtMileageTotal.Text = (mileageEnd - mileageStart).ToString();
}

Return to the Update Rental Order form and double-click the Rent Start Date date time picker control

Implement the event as follows:

private void dtpRentStartDate_ValueChanged(object sender, EventArgs e)
{
    dtpRentEndDate.Value = dtpRentStartDate.Value;
}

Return to the Update Rental Order form and double-click the Rent End Date control

Implement its Click event as follows:

// This event approximately evaluates the number of days as a
// difference between the end date and the starting date
private void dtpRentEndDate_ValueChanged(object sender, EventArgs e)
{
    DateTime dteStart = dtpRentStartDate.Value;
    DateTime dteEnd   = dtpRentEndDate.Value;

    // Let's calculate the difference in days
    TimeSpan tme = dteEnd - dteStart;
    int days = tme.Days;

    // If the customer returns the car the same day, 
    // we consider that the car was rented for 1 day
    if (days == 0)
        days = 1;

    txtTotalDays.Text = days.ToString();
    // In any case, we will let the clerk specify the actual number of days
}

Return to the Update Rental Order form and double-click the Rental Rates button

Implement its event as follows:

private void btnRentalRates_Click(object sender, EventArgs e)
{
    RentalRates rates = new RentalRates();
    rates.Show();
}

Return to the Update Rental Order form and double-click the Calculate button

Implement its event as follows:

private void btnCalculate_Click(object sender, EventArgs e)
{
    int    Days = 0;
    double RateApplied = 0.00;
    double SubTotal = 0.00;
    double TaxRate = 0.00;
    double TaxAmount = 0.00;
    double OrderTotal = 0.00;

    try
    {
        Days = int.Parse(txtTotalDays.Text);
    }
    catch (FormatException)
    {
        MessageBox.Show("Invalid Number of Days",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    try
    {
        RateApplied = double.Parse(txtRateApplied.Text);
    }
    catch (FormatException)
    {
        MessageBox.Show("Invalid Amount for Rate Applied",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    SubTotal = Days * RateApplied;
    txtSubTotal.Text = SubTotal.ToString("F");

    try
    {
        TaxRate = double.Parse(txtTaxRate.Text);
    }
    catch (FormatException)
    {
        MessageBox.Show("Invalid Tax Rate",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    TaxAmount = SubTotal * TaxRate / 100;
    txtTaxAmount.Text = TaxAmount.ToString("F");

    OrderTotal = SubTotal + TaxAmount;
    txtOrderTotal.Text = OrderTotal.ToString("F");
}

Return to the Update Rental Order form and, under the form, double-click docPrint

Implement its event as follows:

private void docPrint_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawLine(new Pen(Color.Black, 2), 80, 90, 750, 90);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 80, 93, 750, 93);

    string strDisplay = "Bethesda Car Rental";
    System.Drawing.Font fntBoldString = new Font("Times New Roman", 28, FontStyle.Bold);
    e.Graphics.DrawString(strDisplay, fntBoldString, Brushes.Black, 240, 100);

    strDisplay = "Vehicle Rental Order";
    System.Drawing.Font fntRegularString = new System.Drawing.Font("Times New Roman", 22, FontStyle.Regular);
    e.Graphics.DrawString(strDisplay, fntRegularString, Brushes.Black, 280, 150);

    e.Graphics.DrawLine(new Pen(Color.Black, 1), 80, 187, 750, 187);
    e.Graphics.DrawLine(new Pen(Color.Black, 2), 80, 190, 750, 190);

    fntBoldString = new Font("Times New Roman", 12, FontStyle.Bold);
    fntRegularString = new System.Drawing.Font("Times New Roman", 12, FontStyle.Regular);

    e.Graphics.DrawString("Receipt #:  ", fntBoldString, Brushes.Black, 100, 220);
    e.Graphics.DrawString(txtReceiptNumber.Text, fntRegularString, Brushes.Black, 260, 220);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 240, 380, 240);

    e.Graphics.DrawString("Processed By:  ", fntBoldString, Brushes.Black, 420, 220);
    e.Graphics.DrawString(txtEmployeeName.Text, fntRegularString, Brushes.Black, 550, 220);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 240, 720, 240);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 260, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 260, 620, 20));

    e.Graphics.DrawString("Customer", fntBoldString, Brushes.White, 100, 260);

    e.Graphics.DrawString("First Name: ", fntBoldString, Brushes.Black, 100, 300);
    e.Graphics.DrawString(txtCustomerFirstName.Text, fntBoldString, Brushes.Black, 260, 300);
    e.Graphics.DrawString("Last Name: ", fntBoldString, Brushes.Black, 420, 300);
    e.Graphics.DrawString(txtCustomerLastName.Text, fntBoldString, Brushes.Black, 540, 300);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 320, 720, 320);

    e.Graphics.DrawString("Address: ", fntBoldString, Brushes.Black, 100, 330);
    e.Graphics.DrawString(txtCustomerAddress.Text, fntRegularString, Brushes.Black, 260, 330);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 350, 720, 350);

    strDisplay = txtCustomerCity.Text + " " + cbxCustomerStates.Text + " " + txtCustomerZIPCode.Text;
    e.Graphics.DrawString(strDisplay, fntRegularString, Brushes.Black, 260, 360);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 260, 380, 720, 380);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 410, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 410, 620, 20));

    e.Graphics.DrawString("Car Information", fntBoldString, Brushes.White, 100, 410);

    e.Graphics.DrawString("Tag #: ", fntBoldString, Brushes.Black, 100, 450);
    e.Graphics.DrawString(txtTagNumber.Text, fntRegularString, Brushes.Black, 260, 450);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 470, 380, 470);

    e.Graphics.DrawString("Condition: ", fntBoldString, Brushes.Black, 420, 450);
    e.Graphics.DrawString(cbxVehiclesConditions.Text, fntRegularString, Brushes.Black, 530, 450); // ?
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 470, 720, 470);

    e.Graphics.DrawString("Make: ", fntBoldString, Brushes.Black, 100, 480);
    e.Graphics.DrawString(txtMake.Text, fntRegularString, Brushes.Black, 260, 480);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 500, 380, 500);

    e.Graphics.DrawString("Model: ", fntBoldString, Brushes.Black, 420, 480);
    e.Graphics.DrawString(txtModel.Text, fntRegularString, Brushes.Black, 530, 480);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 500, 720, 500);

    e.Graphics.DrawString("Vehicle Condition: ", fntBoldString, Brushes.Black, 100, 510);
    e.Graphics.DrawString(cbxVehiclesConditions.Text, fntRegularString, Brushes.Black, 260, 510);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 530, 380, 530);

    e.Graphics.DrawString("Tank Level: ", fntBoldString, Brushes.Black, 420, 510);
    e.Graphics.DrawString(cbxTanksLevels.Text, fntRegularString, Brushes.Black, 530, 510);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 530, 720, 530);

    e.Graphics.DrawString("Mileage Start:", fntBoldString, Brushes.Black, 100, 540);
    e.Graphics.DrawString(txtMileageStart.Text, fntRegularString, Brushes.Black, 260, 540);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 560, 380, 560);

    e.Graphics.DrawString("Mileage End:", fntBoldString, Brushes.Black, 420, 540);
    e.Graphics.DrawString(txtMileageEnd.Text, fntRegularString, Brushes.Black, 530, 540);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 560, 720, 560);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 590, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 590, 620, 20));

    e.Graphics.DrawString("Order Timing Information", fntBoldString, Brushes.White, 100, 590);

    e.Graphics.DrawString("Start Date:", fntBoldString, Brushes.Black, 100, 620);
    e.Graphics.DrawString(dtpRentStartDate.Value.ToString("D"), fntRegularString, Brushes.Black, 260, 620);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 640, 720, 640);

    e.Graphics.DrawString("End Date:", fntBoldString, Brushes.Black, 100, 650);
    e.Graphics.DrawString(dtpRentEndDate.Value.ToString("D"), fntRegularString, Brushes.Black, 260, 650);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 670, 520, 670);

    e.Graphics.DrawString("Total Days:", fntBoldString, Brushes.Black, 550, 650);
    e.Graphics.DrawString(txtTotalDays.Text, fntRegularString, Brushes.Black, 640, 650);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 550, 670, 720, 670);

    e.Graphics.FillRectangle(Brushes.Gray, new Rectangle(100, 700, 620, 20));
    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(100, 700, 620, 20));

    e.Graphics.DrawString("Order Evaluation", fntBoldString, Brushes.White, 100, 700);

    StringFormat fmtString = new StringFormat();
    fmtString.Alignment = StringAlignment.Far;

    e.Graphics.DrawString("Rate Applied:", fntBoldString, Brushes.Black, 100, 740);
    e.Graphics.DrawString(txtRateApplied.Text, fntRegularString, Brushes.Black, 300, 740, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 760, 380, 760);

    e.Graphics.DrawString("Tax Rate:", fntBoldString, Brushes.Black, 420, 740);
    e.Graphics.DrawString(txtTaxRate.Text, fntRegularString, Brushes.Black, 640, 740, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 760, 720, 760);

    e.Graphics.DrawString("Sub-Total:", fntBoldString, Brushes.Black, 100, 770);
    e.Graphics.DrawString(txtSubTotal.Text, fntRegularString, Brushes.Black, 300, 770, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 100, 790, 380, 790);

    e.Graphics.DrawString("Tax Amount:", fntBoldString, Brushes.Black, 420, 770);
    e.Graphics.DrawString(txtTaxAmount.Text, fntRegularString, Brushes.Black, 640, 770, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 790, 720, 790);

    e.Graphics.DrawString("Order Total:", fntBoldString, Brushes.Black, 420, 800);
    e.Graphics.DrawString(txtOrderTotal.Text, fntRegularString, Brushes.Black, 640, 800, fmtString);
    e.Graphics.DrawLine(new Pen(Color.Black, 1), 420, 820, 720, 820);
}

Return to the Update Rental Order form and double-click the Print button

Implement the event as follows:

private void btnPrint_Click(object sender, EventArgs e)
{
    if (dlgPrint.ShowDialog() == DialogResult.OK)
        docPrint.Print();
}

Return to the Update Rental Order form and double-click the Print Preview button

Implement the event as follows:

private void btnPrintPreview_Click(object sender, EventArgs e)
{
    dlgPrintPreview.ShowDialog();
}

To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental1 -> Add -> Windows Form...
Set the Name to RentalOrders and click Add

Design the form as follows:

Bethesda Car Rental: Rental Orders

Control

(Name)

Text

Other Properties

ListView

lvwRentalOrders

Anchor: Top, Bottom, Left, Right

(Name)	Text	TextAlign	Width
colReceiptOrderNumber	Receipt #
colProcessedDate	Date Processed	Center	90
colEmployee	Processed By		80
colCustomerFirstName	Customer First Name		110
colCustomerLastName	Last Name		65
colCustomerAddress	Address		160
colCustomerCity	City		70
colCustomerState	State		40
colCustomerZIPCode	ZIP Code
colVehicle	Vehicle
colVehicleCondition	Condition
colTank	Tank Level		70
colMileageStart	Mileage Start	Right	75
colMileageEnd	Mileage End	Right	75
colTotalMileage	Total Miles	Right	65
colRentStartDate	Start Date	Center	70
colRentEndDate	End Date	Center	70
colDaysTotal	Total Days	Right	65
colRateApplied	Rate Applied	Right	75
colSubTotal	Sub-Total	Right
colTaxRate	Tax Rate	Right
colTaxAmount	Tax Amt	Right	55
colOrderTotal	Order Total	Right	65
colOrderStatus	Order Status		150

Button

btnNewRentalOrder

New Rental Order ...

Anchor: Bottom, Right

Button

btnUpdateRentalOrder

Update Rental Order ...

Anchor: Bottom, Right

Button

btnClose

Anchor: Bottom, Right

In the Solution Explorer, right-click Form1.cs and click Rename
Type BethesdaCarRental.cs and press Enter twice

Design the form as follows:

Control	Text	Name
Button	btnRentalOrders	Rental Orders...
Button	btnVehicles	Vehicles...
Button	btnEmployees	Employees...
Button	btnClose	Close

Double-click an unoccupied area of the form and change the document as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace BethesdaCarRental2
{
    public partial class BethesdaCarRental : Form
    {
        public BethesdaCarRental()
        {
            InitializeComponent();
        }

        private void BethesdaCarRental_Load(object sender, EventArgs e)
        {
	    // If the directory and the sub-directory don't exist, create them
            Directory.CreateDirectory(@"C:\Microsoft Visual C# Application Design\Bethesda Car Rental");
        }
    }
}

Double-click the Rental Orders button and implement its event as follows:

private void btnRentalOrders_Click(object sender, EventArgs e)
{
    RentalOrders ros = new RentalOrders();
    ros.Show();
}

Return to the Bethesda Car Rental form and double-click the Vehicles button

Implement the event as follows:

private void btnVehicles_Click(object sender, EventArgs e)
{
    Vehicles cars = new Vehicles();
    cars.Show();
}

Return to the Bethesda Car Rental form and double-click the Employees button

Implement the event as follows:

private void btnEmployees_Click(object sender, EventArgs e)
{
    Employees staff = new Employees();
    staff.Show();
}

Return to the Bethesda Car Rental form and double-click the Close button

Implement the event as follows:

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

Save all

XPath in .NET

As mentioned earlier, Microsoft supports XPath in the MSXML library and in the .NET Framework. For our application, we will use XPath as it is implemented in the .NET Framework. As you may know already, the .NET Framework provides various classes to support XML. These are the XmlDocument class(which gives access to the whole XML document), the XmlElement class (which represents an element), the XmlNode class (which represents a node), and the XmlNodeList class (which represents a collection of elements), among many other classes. These classes are defined in the System.Xml namespace. The .NET Framework supports XPath through the System.Xml.XPath namespace.

To provide the ability to use XPath, the XmlNode class is equipped with the overloaded SelectNodes() method. One of the versions takes an XPath expression as a string. If the XmlNode.SelectNodes() method succeeds, it produces an XmlNodeList collection.

Locating the Root of An XML Document

To get to the root of an XML document, pass / as the argument to XmlElement.SelectNodes(string xpath) method as /. An alternative to pass /* or the name of the root preceded by /.

Locating the Child Nodes of the Root

To locate the direct child nodes of the root, pass the argument as /RootName/ChildOfRootName.

Practical Learning: Accessing the Child Nodes of an Element

Display the Employees form and double-click an unoccupied area of its body

Change the document as follows:

internal void ShowEmployees()
{
    XmlDocument xdEmployees = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Employees.xml";

    if (File.Exists(strFileName))
    {
        lvwEmployees.Items.Clear();

        xdEmployees.Load(strFileName);
        XmlNodeList xnlEmployeesNumbers = xdEmployees.DocumentElement.SelectNodes("/Employees/Employee/EmployeeNumber");

        foreach (XmlNode xnEmployee in xnlEmployeesNumbers)
        {
            ListViewItem lviEmployee = new ListViewItem(xnEmployee.InnerText); // Employee Number

            lviEmployee.SubItems.Add(xnEmployee.NextSibling.InnerText); // First Name
            lviEmployee.SubItems.Add(xnEmployee.NextSibling.NextSibling.InnerText); // Last Name
            lviEmployee.SubItems.Add(xnEmployee.NextSibling.NextSibling.NextSibling.InnerText); // Title

            lvwEmployees.Items.Add(lviEmployee);
        }
    }
}

private void Employees_Load(object sender, EventArgs e)
{
    ShowEmployees();
}

Return to the Employees form and double-click the Close button

Implement the event as follows:

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

Locating the Grand-Children of a Node

To access the grandchildren of a node, separate its name and that of the grand-child name with /*/. If you have many elements that share the same name in your XML document, pass their name preceded by //. You can also precede // with a period.

Practical Learning: Accessing Specific Nodes

Display the Vehicles form and click its title bar to select the form itself (or, in the top combo box of the Properties window, select Vehicles System.Windows.Forms.Form)
On the Properties window, click the Events button and double-click Load

Change the document as follows:

private void ShowVehicles()
{
    XmlDocument xdVehicles = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicles.xml";

    if (File.Exists(strFileName))
    {
        tvwVehicles.Nodes.Clear();
        lvwVehicles.Items.Clear();

        xdVehicles.Load(strFileName);
        XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("//TagNumber");
        XmlNodeList xnlCategories = xdVehicles.DocumentElement.SelectNodes("//Category");
        XmlNodeList xnlAvailabilities = xdVehicles.DocumentElement.SelectNodes("//Availability");

        List lstCategories = new List();
        List lstAvailabilities = new List();

        TreeNode nodBCR = tvwVehicles.Nodes.Add("Bethesda Car Rental");
        TreeNode nodCategories = nodBCR.Nodes.Add("Categories");
        TreeNode nodAvailabilities = nodBCR.Nodes.Add("Availabilities");

        foreach (XmlNode xnCategory in xnlCategories)
        {
            if (!(lstCategories.Contains(xnCategory.InnerText)))
                lstCategories.Add(xnCategory.InnerText);
        }
        foreach (XmlNode xnAvailability in xnlAvailabilities)
        {
            if (!(lstAvailabilities.Contains(xnAvailability.InnerText)))
                lstAvailabilities.Add(xnAvailability.InnerText);
        }

        foreach (string strCategory in lstCategories)
            nodCategories.Nodes.Add(strCategory);
        foreach (string strAvailability in lstAvailabilities)
            nodAvailabilities.Nodes.Add(strAvailability);

        foreach (XmlNode xnVehicle in xnlVehicles)
        {
            ListViewItem lviVehicle = new ListViewItem(xnVehicle.InnerText); // Tag Number

            lviVehicle.SubItems.Add(xnVehicle.NextSibling.InnerText); // Make
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.InnerText); // Model
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.InnerText); // Doors
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Passengers
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Condition
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Category
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Availability
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Picture File

            lvwVehicles.Items.Add(lviVehicle);
        }
    }

    pbxVehicle.Image = Image.FromFile(@"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicle1.jpg");
}

private void Vehicles_Load(object sender, EventArgs e)
{
    ShowVehicles();
}

Return to the Vehicles form and double-click the Close button

Implement the event as follows:

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

XPath and Arrays

The results of an XPath expression are stored in a collection treated as an array. The positions start at 1. The second is at index 2, until the end. To access an individual result, use the square brackets as done in C-based languages.

To get only the nodes that have a specific section, pass the name of that section to the square brackets of the parent element.

Practical Learning: Accessing a Node by Value

Display the New Rental Order form and click the Employee # text box

In the Events section of the Properties, double-click Leave and implement the event as follows:

private void txtEmployeeNumber_Leave(object sender, EventArgs e)
{
    XmlDocument xdEmployees = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Employees.xml";

    if (File.Exists(strFileName))
    {
        xdEmployees.Load(strFileName);
        XmlNodeList xnlEmployees = xdEmployees.DocumentElement.SelectNodes("/Employees/Employee/EmployeeNumber[.='" + txtEmployeeNumber.Text + "']");

        foreach (XmlNode xnEmployee in xnlEmployees)
        {
            txtEmployeeName.Text = xnEmployee.NextSibling.InnerText + " " + xnEmployee.NextSibling.NextSibling.InnerText;
        }
    }
}

Return to the New Rental Order form and click the Tag Number text box

In the Events section of the Properties, double-click Leave and implement the event as follows:

private void txtTagNumber_Leave(object sender, EventArgs e)
{
    XmlDocument xdVehicles = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicles.xml";

    if (File.Exists(strFileName))
    {
        xdVehicles.Load(strFileName);
        XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("/Vehicles/Vehicle/TagNumber[ .= '" + txtTagNumber.Text + "']");

        foreach (XmlNode xnVehicle in xnlVehicles)
        {
            txtMake.Text = xnVehicle.NextSibling.InnerText;
            txtModel.Text = xnVehicle.NextSibling.NextSibling.InnerText;
            cbxVehiclesConditions.Text = xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
        }
    }
}

Display the Update Rental Order form and click the Employee # text box

In the Events section of the Properties, double-click Leave and implement the event as follows:

private void txtEmployeeNumber_Leave(object sender, EventArgs e)
{
    XmlDocument xdEmployees = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Employees.xml";

    if (File.Exists(strFileName))
    {
        xdEmployees.Load(strFileName);
        XmlNodeList xnlEmployees = xdEmployees.DocumentElement.SelectNodes("/Employees/Employee/EmployeeNumber[.='" + txtEmployeeNumber.Text + "']");

        foreach (XmlNode xnEmployee in xnlEmployees)
        {
            txtEmployeeName.Text = xnEmployee.NextSibling.InnerText + " " + xnEmployee.NextSibling.NextSibling.InnerText;
        }
    }
}

Return to the Update Rental Order form and click the Tag Number text box

In the Events section of the Properties, double-click Leave and implement the event as follows:

private void txtTagNumber_Leave(object sender, EventArgs e)
{
    XmlDocument xdVehicles = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicles.xml";

    if (File.Exists(strFileName))
    {
        xdVehicles.Load(strFileName);
        XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("/Vehicles/Vehicle/TagNumber[ .= '" + txtTagNumber.Text + "']");

        foreach (XmlNode xnVehicle in xnlVehicles)
        {
            txtMake.Text = xnVehicle.NextSibling.InnerText;
            txtModel.Text = xnVehicle.NextSibling.NextSibling.InnerText;
            cbxVehiclesConditions.Text = xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
        }
    }
}

XPath Functions

The XPath language provides the position() function. To use it, type it in the square brackets of the node and assign the desired position to it.

To access the last child node of a node, call the last() function.

Practical Learning: Accessing the Last Child Node of a Node

Display the New Rental Order form and double-click an unoccupied area of its body

Change the document as follows:

private void InitializeNewRentalOrder()
{
    int iReceiptNumber = 100000;
    XmlDocument xdRentalOrders = new XmlDocument();
    List lstReceiptNumbers = new List();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\RentalOrders.xml";

    if (File.Exists(strFileName))
    {
        xdRentalOrders.Load(strFileName);
        // Get the receipt number of the last rental order
        XmlNodeList xnlRentalOrders = xdRentalOrders.DocumentElement.SelectNodes("/RentalOrders/RentalOrder[last()]/ReceiptNumber");

        foreach (XmlNode xnRentalOrder in xnlRentalOrders)
        {
            iReceiptNumber = int.Parse(xnRentalOrder.InnerText);
        }

        txtReceiptNumber.Text = (iReceiptNumber + 1).ToString();
    }
}

private void NewRentalOrder_Load(object sender, EventArgs e)
{
    InitializeNewRentalOrder();
}

Return to the New Rental Order form and double-click the Close button

Implement the event as follows:

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

Boolean Node Searching

To visit two nodes, add a first combination that includes one of the names of child nodes. Include a second pair of square brackets with the other name. Here is an example:

XmlNodeList xnlVideos = xeVideo.SelectNodes("/videos/video[format][categories]");

An alternative is to write the names of two child nodes separated by the and operator. Here is an example:

XmlNodeList xnlVideos = xeVideo.SelectNodes("//videos/video[format and categories]");

To produce the parent nodes that include one or the other child node, use the or operator. Here is an example:

XmlNodeList xnlVideos = xeVideo.SelectNodes("/videos/video[cast-members or categories]");

To exclude a node or value from a result, use the not function. To use it, pass the name of the node to it. Here is an example:

XmlNodeList xnlVideos = xeVideo.SelectNodes("/videos/video[not(cast-members)]");

Sets Combination

To combine two results into one, use the | operator. Here is an example:

XmlNodeList xnlVideos = xeVideo.SelectNodes("//cast-members[actor='Danny DeVito'] | //cast-members[actor='Eddie Murphy']");

Boolean Operations

The XPath language supports various Boolean operators such as =, < (or <), <= (or &lt=), > (or >), >= )or >=), and !=. These operators can be used on node names and constant values, or among nodes names.

XPath Axes

An XPath axis is a technique to locate a node or a collection of nodes based on a path. This is done using some keywords. The keyword is followed by ::.

The child keyword is used to locate a child node.

Practical Learning: Accessing a Child Node

Display the Rental Orders form and double-click an unoccupied area of its body

Change the document as follows:

private void ShowRentalOrders()
{
    XmlDocument xdEmployees = new XmlDocument();
    XmlDocument xdRentalOrders = new XmlDocument();
    string strRentalOrdersFile = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\RentalOrders.xml";

    if (File.Exists(strRentalOrdersFile))
    {
        xdRentalOrders.Load(strRentalOrdersFile);
        // The "child" keyword is optional (you can omit it
        XmlNodeList xnlRentalOrders = xdRentalOrders.DocumentElement.SelectNodes("//child::ReceiptNumber");

        lvwRentalOrders.Items.Clear();

        foreach (XmlNode xnRentalOrder in xnlRentalOrders)
        {
            ListViewItem lviRentalOrder = new ListViewItem(xnRentalOrder.InnerText); // Receipt #

            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.InnerText); // Date Processed
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.InnerText); // Employee Number
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.InnerText); // Custimer First Name
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Customer Last Name
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Customer Address
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Customer City
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Cusomer State
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Customer ZIP Code
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Vehicle Tag Number
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Vehicle Condition
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Tank Level
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Mileage Start
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Mileage End
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Mileage Total
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Start Date
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // End Date
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Total Days
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Rate Applied
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Sub-Total
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Tax Rate
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Tax Amount
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Order Total
            lviRentalOrder.SubItems.Add(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Order Status

            lvwRentalOrders.Items.Add(lviRentalOrder);
        }
    }
}

private void RentalOrders_Load(object sender, EventArgs e)
{
    ShowRentalOrders();
}

Parent Nodes

The parent keyword is used to get the parent of an element.

Practical Learning: Accessing a Parent Node

Display the Update Rental Orders form and double-click the Open Rental Order button

Implement the event as follows:

private void btnOpen_Click(object sender, EventArgs e)
{
    XmlDocument xdEmployees = new XmlDocument();
    XmlDocument xdRentalOrders = new XmlDocument();
    string strRentalOrdersFile = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\RentalOrders.xml";

    if (string.IsNullOrEmpty(txtReceiptNumber.Text))
    {
        MessageBox.Show("You must provide a receipt number.",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
        return;
    }

    if (File.Exists(strRentalOrdersFile))
    {
        xdRentalOrders.Load(strRentalOrdersFile);
        // The "parent" keyword is optional (you can omit it
        XmlNodeList xnlRentalOrders = xdRentalOrders.DocumentElement.SelectNodes("//parent::ReceiptNumber[.='" + txtReceiptNumber.Text + "']");

        foreach (XmlNode xnRentalOrder in xnlRentalOrders)
        {
            dtpDateProcessed.Value = DateTime.Parse(xnRentalOrder.NextSibling.InnerText);
            txtEmployeeNumber.Text = xnRentalOrder.NextSibling.NextSibling.InnerText;
            
            txtEmployeeNumber_Leave(sender, e);
            
            txtCustomerFirstName.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.InnerText;
            txtCustomerLastName.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtCustomerAddress.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtCustomerCity.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            cbxCustomerStates.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtCustomerZIPCode.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtTagNumber.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
                    
            txtTagNumber_Leave(sender, e);

            cbxVehiclesConditions.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            cbxTanksLevels.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtMileageStart.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtMileageEnd.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
                    
            txtMileageEnd_Leave(sender, e);

            dtpRentStartDate.Value = DateTime.Parse(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText);
            dtpRentEndDate.Value = DateTime.Parse(xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText);

            dtpRentEndDate_ValueChanged(sender, e);

            txtRateApplied.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText; //
            txtTaxRate.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            
            btnCalculate_Click(sender, e);
            
            cbxOrderStatus.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
            txtNotes.Text = xnRentalOrder.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText;
        }
    }
}

The Ancestors of a Node

To get the ancestors of a node, precede its name with the ancestor keyword. Here is an example:

The Descendants of a Node

To get the descendants of a node, precede its name with the descendant keyword.

Practical Learning: Accessing the Descendants of a Node

Display the Vehicles form and click the tree view
On the Properties window, click Events and double-click NodeMouseClick

Implement the event as follows:

private void tvwVehicles_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
{
    XmlDocument xdVehicles = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\Vehicles.xml";

    xdVehicles.Load(strFileName);
    lvwVehicles.Items.Clear();

    if ((e.Node.Text == "Bethesda Car Rental") ||
        (e.Node.Text == "Categories") ||
        (e.Node.Text == "Availabilities"))
    {
        // The descendant:: axis is optional
        XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("/descendant::TagNumber"); // /descendant::TagNumber[.='" + e.Item.Text + "']");

        foreach (XmlNode xnVehicle in xnlVehicles)
        {
            ListViewItem lviVehicle = new ListViewItem(xnVehicle.InnerText); // Tag Number

            lviVehicle.SubItems.Add(xnVehicle.NextSibling.InnerText); // Make
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.InnerText); // Model
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.InnerText); // Doors
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Passengers
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Condition
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Category
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Availability
            lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.NextSibling.InnerText); // Picture File
            lvwVehicles.Items.Add(lviVehicle);
        }
    }
    else
    {
        try
        {
            if (e.Node.Parent.Text == "Categories")
            {
                XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("/Vehicles/Vehicle/descendant::Category[.='" + e.Node.Text + "']");

                foreach (XmlNode xnVehicle in xnlVehicles)
                {
                    ListViewItem lviVehicle = new ListViewItem(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Tag Number

                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Make
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Model
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Doors
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.InnerText); // Passengers
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.InnerText); // Category
                    lviVehicle.SubItems.Add(xnVehicle.InnerText); // Condition
                    lviVehicle.SubItems.Add(xnVehicle.NextSibling.InnerText); // Availability
                    lviVehicle.SubItems.Add(xnVehicle.NextSibling.NextSibling.InnerText); // Picture File

                    lvwVehicles.Items.Add(lviVehicle);
                }
            }
            else if (e.Node.Parent.Text == "Availabilities")
            {
                XmlNodeList xnlVehicles = xdVehicles.DocumentElement.SelectNodes("/Vehicles/Vehicle/descendant::Availability[.='" + e.Node.Text + "']");

                foreach (XmlNode xnVehicle in xnlVehicles)
                {
                    ListViewItem lviVehicle = new ListViewItem(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Tag Number
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Make
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Model
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Doors
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.PreviousSibling.InnerText); // Passengers
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.PreviousSibling.InnerText); // Category
                    lviVehicle.SubItems.Add(xnVehicle.PreviousSibling.InnerText); // Condition
                    lviVehicle.SubItems.Add(xnVehicle.InnerText); // Availability
                    lviVehicle.SubItems.Add(xnVehicle.NextSibling.InnerText); // Picture File

                    lvwVehicles.Items.Add(lviVehicle);
                }
            }
        }
        catch (System.NullReferenceException nre)
        {
            MessageBox.Show(nre.Message);
        }
    }

    pbxVehicle.Image = Image.FromFile(@"C:\Microsoft Visual C# Application Design\Vehicle1.jpg");
}

Return to the Vehicles form and double-click the Close button

Implement the event as follows:

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

The Previous Sibling of a Node

To get the collection of nodes that come before a certain node, precede its name with the preceding keyword. If you want to exclude the node itself from the result, in other words if you want to get only the next sibliing of the same level, use the preceding-sibling keyword.

The Next Sibling a Node

The following keyword is used to get the next node(s) that come after the referenced one but of the same tree level.

Practical Learning: Following a Node

Return to the Update Rental Orders form and double-click the Update Rental Order button

Implement the event as follows:

private void btnUpdateRentalOrder_Click(object sender, EventArgs e)
{
    XmlDocument xdEmployees = new XmlDocument();
    XmlDocument xdRentalOrders = new XmlDocument();
    string strFileName = @"C:\Microsoft Visual C# Application Design\Bethesda Car Rental\RentalOrders.xml";

    if (string.IsNullOrEmpty(txtReceiptNumber.Text))
    {
        MessageBox.Show("You must provide a receipt number.",
                        "Bethesda Car Rental",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
        return;
    }

    if (File.Exists(strFileName))
    {
        xdRentalOrders.Load(strFileName);
        // The "following" keyword is optional (you can omit it
        XmlNodeList xnlRentalOrders = xdRentalOrders.DocumentElement.SelectNodes("//following::ReceiptNumber[.='" + txtReceiptNumber.Text + "']");

        foreach (XmlNode xnRentalOrder in xnlRentalOrders)
        {
            xnRentalOrder.ParentNode.InnerXml = "<ReceiptNumber>" + txtReceiptNumber.Text + "</ReceiptNumber>" +
                                                "<DateProcessed>" + dtpDateProcessed.Value.ToShortDateString() + "</DateProcessed>" +
                                                "<EmployeeNumber>" + txtEmployeeNumber.Text + "</EmployeeNumber>" +
                                                "<CustomerFirstName>" + txtCustomerFirstName.Text + "</CustomerFirstName>" +
                                                "<CustomerLastName>" + txtCustomerLastName.Text + "</CustomerLastName>" +
                                                "<CustomerAddress>" + txtCustomerAddress.Text + "</CustomerAddress>" +
                                                "<CustomerCity>" + txtCustomerCity.Text + "</CustomerCity>" +
                                                "<CustomerState>" + cbxCustomerStates.Text + "</CustomerState>" +
                                                "<CustomerZIPCode>" + txtCustomerZIPCode.Text + "</CustomerZIPCode>" +
                                                "<VehicleTagNumber>" + txtTagNumber.Text +  "</VehicleTagNumber>" +
                                                "<VehicleCondition>" + cbxVehiclesConditions.Text +  "</VehicleCondition>" +
                                                "<TankLevel>" + cbxTanksLevels.Text +  "</TankLevel>" +
                                                "<MileageStart>" + txtMileageStart.Text +  "</MileageStart>" +
                                                "<MileageEnd>" + txtMileageEnd.Text + "</MileageEnd>" +
                                                "<MileageTotal>" + txtMileageTotal.Text + "</MileageTotal>" +
                                                "<RentStartDate>" + dtpRentStartDate.Value.ToShortDateString() + "</RentStartDate>" +
                                                "<RentEndDate>" + dtpRentStartDate.Value.ToShortDateString() + "</RentEndDate>" +
                                                "<TotalDays>" + txtTotalDays.Text + "</TotalDays>" +
                                                "<RateApplied>" + txtRateApplied.Text +  "</RateApplied>" +
                                                "<SubTotal>" + txtSubTotal.Text + "</SubTotal>" +
                                                "<TaxRate>" + txtTaxRate.Text +  "</TaxRate>" +
                                                "<TaxAmount>" + txtTaxAmount.Text + "</TaxAmount>" +
                                                "<OrderTotal>" + txtOrderTotal.Text + "</OrderTotal>" +
                                                "<OrderStatus>" + cbxOrdersStatus.Text +  "</OrderStatus>" +
                                                "<Notes>" + txtNotes.Text +  "</Notes>";
        }

        xdRentalOrders.Save(strFileName);
        Close();
    }
}

Return to the Update Rental Order form and double-click the Close button

Implement the event as follows:

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

Display the Rental Orders form and double-click the New Rental Order button
Return to the Rental Orders form and double-click the Update Rental Order button
Return to the Update Rental Order form and double-click the Close button

Implement the events as follows:

private void btnNewRentalOrder_Click(object sender, EventArgs e)
{
    NewRentalOrder nro = new NewRentalOrder();
    nro.ShowDialog();
    ShowRentalOrders();
}

private void btnUpdateRentalOrder_Click(object sender, EventArgs e)
{
    UpdateRentalOrder uro = new UpdateRentalOrder();
    uro.ShowDialog();
    ShowRentalOrders();
}

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