Introduction

A data relationship is a type of relationship that is created between two tables so that information can flow from one object to another. This makes it possible and easy for effective data entry.

In this application, we explore some of the features of data relationships as they are implemented in the DataSet class of the .NET Framework. The application we create is a fictitious car rental company (Bethesda Car Rental) where customers can reserve, rent, and/or take possession of a car.

1. Start Microsoft Visual Basic and create a new Windows Forms Application named BethesdaCarRental2
2. To add a new form to the project, in the Solution Explorer, right-click BethesdaCarRental2 -> Add -> Windows Form...
3. Set the Name to OrderProcessing and press Enter
4. Design the form as follows:
    

   Control Text Name Other Properties Label Processed By:   AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft Label Employee #:     MaskedTextBox   cbxEmployeeID   Label Employee Name:     TextBox   txtEmployeeName   Label Processed For   AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft Label Driver's Lic #:     TextBox   cbxCustomerID   Label Cust Name:     TextBox   txtCustomerName   Label Address:     TextBox   txtCustomerAddress   Label City:     TextBox   txtCustomerCity   Label State:     ComboBox   cbxCustomerStates DropDownStyle: DropDownList Sorted: True Items: AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI, WY Label ZIP Code     TextBox   txtCustomerZIPCode   Label Car Selected   AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft Label Tag Number:     TextBox   cbxCarID   Label Car Condition:     ComboBox   cbxCarConditions Sorted: True Items: Needs Repair Drivable Excellent Label Make:     TextBox   txtMake   Label Model:     TextBox   txtModel   Label Year:     TextBox   txtCarYear   label Tank Level:     ComboBox   cbxTankLevels Empty 1/4 Empty 1/2 Full 3/4 Full Full Label Mileage Start:     TextBox   txtMileageStart TextAlign: Right Label Mileage }:     TextBox   txtMileage} TextAlign: Right Label Order Timing   AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft Label Start Date:     DateTimePicker   dtpStartDate   Label End Date:     DateTimePicker   dtpEndDate   Label Days:     TextBox 0 txtDays TextAlign: Right Label Order Status     ComboBox   cbxOrderStatus Items: Car On Road Car Returned Order Reserved Label Order Evaluation   AutoSize: False BackColor: Gray BorderStyle: FixedSingle ForeColor: White TextAlign: MiddleLeft Label Rate Applied:     TextBox 0.00 txtRateApplied TextAlign: Right Button Rental Rates btnRentalRates   Label Sub-Total:     TextBox 0.00 txtSubTotal TextAlign: Right Button Calculate btnCalculate   Label Tax Rate:     TextBox 7.75 txtTaxRate TextAlign: Right Label %     Button Save btnSave   Label Tax Amount:     TextBox 0.00 txtTaxAmount TextAlign: Right Button Print... btnPrint   Label Order Total:     TextBox 0.00 txtOrderTotal TextAlign: Right Button Print Preview... btnPrintPreview   Label Receipt #:     TextBox 0 txtReceiptNumber   Button Open btnOpen   Button New Rental Order/Reset btnNewRentalOrder   Button Close btnClose

5. Right-click the Order Processing form and click View Code
6. Above the Start Date date time picker control
   

   Imports System.IO
   
   Public Class OrderProcessing
   
   End Class

7. In the Class Name combo box, select dtpStartDate
8. In the Method Name combo box, select ValueChanged and implement the event as follows:
   

   Imports System.IO
   
   Public Class OrderProcessing
   
       Private Sub dtpStartDateValueChanged(ByVal sender As Object, 
                                             ByVal e As System.EventArgs) 
                                             Handles dtpStartDate.ValueChanged
           dtpEndDate.Value = dtpStartDate.Value
       End Sub
   End Class

9. In the Class Name combo box, select dtpEndDate
10. In the Method Name combo box, select ValueChanged and implement the event as follows:
    

    ' This event approximately evaluates the number of days as a
    ' difference between the end date and the starting date
    Private Sub dtpEndDateValueChanged(ByVal sender As Object, 
                                        ByVal e As System.EventArgs) 
                                        Handles dtpEndDate.ValueChanged
        Dim Days As Integer
    
        Dim dteStart As DateTime = dtpStartDate.Value
        Dim dteEnd As DateTime = dtpEndDate.Value
    
        ' Let's calculate the difference in days
        Dim tme As TimeSpan = dteEnd - dteStart
        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 Then
            Days = 1
        End If
    
        txtDays.Text = Days
        ' At any case, we will let the clerk specify the actual number of days
    End Sub

11. In the Class Name combo box, select btnCalculate
12. In the Method Name combo box, select Click and implement the event as follows:
    

    Private Sub btnCalculateClick(ByVal sender As Object, 
                                       ByVal e As System.EventArgs) 
                                       Handles btnCalculate.Click
            Dim Days As Integer
            Dim RateApplied As Double
            Dim SubTotal As Double
            Dim TaxRate As Double
            Dim TaxAmount As Double
            Dim OrderTotal As Double
    
            Try
                Days = CInt(txtDays.Text)
            Catch Exc As FormatException
                MsgBox("Invalid Number of Days")
            End Try
    
            Try
                RateApplied = CDbl(txtRateApplied.Text)
            Catch Exc As FormatException
                MsgBox("Invalid Amount for Rate Applied")
            End Try
    
            SubTotal = Days * RateApplied
            txtSubTotal.Text = FormatNumber(SubTotal)
    
            Try
                TaxRate = CDbl(txtTaxRate.Text)
            Catch Exc As FormatException
                MsgBox("Invalid Tax Rate")
            End Try
    
            TaxAmount = SubTotal * TaxRate / 100
            txtTaxAmount.Text = FormatNumber(TaxAmount)
    
            OrderTotal = SubTotal + TaxAmount
            txtOrderTotal.Text = FormatNumber(OrderTotal)
    End Sub

13. Return to the Order Processing form
14. From the Printing section of the Toolbox, click PrintDocument and click the form
15. In the Properties window, set its (Name) to docPrint and press Enter
16. Right-click the form and click View Code
17. In the Class Name combo box, select docPrint
18. In the Method Name combo box, select PrintPage and implement the event as follows:
    

    Private Sub docPrintPrintPage(ByVal sender As Object, 
                    ByVal e As System.Drawing.Printing.PrintPageEventArgs) 
                                   Handles docPrint.PrintPage
            e.Graphics.DrawLine(New Pen(Color.Black, 2), 80, 90, 750, 90)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 80, 93, 750, 93)
    
            Dim strDisplay As String = "Bethesda Car Rental"
            Dim fntString As Font = New Font("Times New Roman", 28, 
                            FontStyle.Bold)
            e.Graphics.DrawString(strDisplay, fntString, 
                            Brushes.Black, 240, 100)
    
            strDisplay = "Car Rental Order"
            fntString = New System.Drawing.Font("Times New Roman", 22, 
                            FontStyle.Regular)
            e.Graphics.DrawString(strDisplay, fntString, 
                            Brushes.Black, 320, 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)
    
            fntString = New System.Drawing.Font("Times New Roman", 12, 
                    FontStyle.Bold)
            e.Graphics.DrawString("Receipt #:  ", fntString, 
                    Brushes.Black, 100, 220)
            fntString = New System.Drawing.Font("Times New Roman", 12, 
                    FontStyle.Regular)
            e.Graphics.DrawString(txtReceiptNumber.Text, fntString, 
                                      Brushes.Black, 260, 220)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 240, 380, 240)
    
            fntString = New System.Drawing.Font("Times New Roman", 12, 
                    FontStyle.Bold)
            e.Graphics.DrawString("Processed By:  ", fntString, 
                    Brushes.Black, 420, 220)
            fntString = New System.Drawing.Font("Times New Roman", 12, 
                    FontStyle.Regular)
            e.Graphics.DrawString(txtEmployeeName.Text, fntString, 
                                      Brushes.Black, 550, 220)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 420, 240, 720, 240)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
    
            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", fntString, 
                                      Brushes.White, 100, 260)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Driver's License #: ", fntString, 
                                      Brushes.Black, 100, 300)
            e.Graphics.DrawString("Name: ", fntString, 
                                     Brushes.Black, 420, 300)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(cbxCustomerID.Text, fntString, 
                                      Brushes.Black, 260, 300)
            e.Graphics.DrawString(txtCustomerName.Text, fntString, 
                                      Brushes.Black, 540, 300)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 320, 720, 320)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Address: ", fntString, 
                                      Brushes.Black, 100, 330)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtCustomerAddress.Text, fntString, 
                                      Brushes.Black, 260, 330)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 350, 720, 350)
    
            strDisplay = txtCustomerCity.Text & " " & 
                                 cbxCustomerStates.Text & " " & 
                txtCustomerZIPCode.Text
            fntString = New System.Drawing.Font("Times New Roman", 
                                                12, FontStyle.Regular)
            e.Graphics.DrawString(strDisplay, fntString, 
                                      Brushes.Black, 260, 360)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 260, 380, 720, 380)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
    
            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", fntString, 
                                      Brushes.White, 100, 410)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Tag #: ", fntString, 
                                      Brushes.Black, 100, 450)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(cbxCarID.Text, fntString, 
                                      Brushes.Black, 260, 450)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 470, 380, 470)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Year: ", fntString, 
                                      Brushes.Black, 420, 450)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtCarYear.Text, fntString, 
                                      Brushes.Black, 530, 450)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 420, 470, 720, 470)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Make: ", fntString, 
                                      Brushes.Black, 100, 480)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtMake.Text, fntString, 
                                      Brushes.Black, 260, 480)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 500, 380, 500)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Model: ", fntString, 
                                      Brushes.Black, 420, 480)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtModel.Text, fntString, 
                                      Brushes.Black, 530, 480)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 420, 500, 720, 500)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Car Condition: ", fntString, 
                                      Brushes.Black, 100, 510)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(cbxCarConditions.Text, fntString, 
                                      Brushes.Black, 260, 510)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 100, 530, 380, 530)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Tank Level: ", fntString, 
                                      Brushes.Black, 420, 510)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(cbxTankLevels.Text, fntString, 
                                      Brushes.Black, 530, 510)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 420, 530, 720, 530)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Mileage Start:", fntString, 
                                      Brushes.Black, 100, 540)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtMileageStart.Text, fntString, 
                                      Brushes.Black, 260, 540)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                100, 560, 380, 560)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Mileage }:", fntString, 
                              Brushes.Black, 420, 540)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtMileageEnd.Text, fntString, 
                              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))
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Order Timing Information", fntString, 
                              Brushes.White, 100, 590)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Start Date:", fntString, 
                               Brushes.Black, 100, 620)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(dtpStartDate.Value.ToString("D"), 
                                  fntString, Brushes.Black, 260, 620)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                100, 640, 720, 640)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("End Date:", fntString, 
                              Brushes.Black, 100, 650)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(dtpEndDate.Value.ToString("D"), fntString, 
                              Brushes.Black, 260, 650)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                100, 670, 520, 670)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Days:", fntString, 
                              Brushes.Black, 550, 650)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtDays.Text, fntString, 
                                      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))
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Order Evaluation", fntString, 
                              Brushes.White, 100, 700)
    
            Dim fmtString As StringFormat = New StringFormat
            fmtString.Alignment = StringAlignment.Far
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Rate Applied:", fntString, 
                              Brushes.Black, 100, 740)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtRateApplied.Text, fntString, 
                              Brushes.Black, 300, 740, fmtString)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                100, 760, 380, 760)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Tax Rate:", fntString, 
                              Brushes.Black, 420, 740)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtTaxRate.Text, fntString, 
                              Brushes.Black, 640, 740, fmtString)
            e.Graphics.DrawString("%", fntString, 
                              Brushes.Black, 640, 740)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                420, 760, 720, 760)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Sub-Total:", fntString, 
                              Brushes.Black, 100, 770)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtSubTotal.Text, fntString, 
                              Brushes.Black, 300, 770, fmtString)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                100, 790, 380, 790)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Tax Amount:", fntString, 
                                      Brushes.Black, 420, 770)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtTaxAmount.Text, fntString, 
                              Brushes.Black, 640, 770, fmtString)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                420, 790, 720, 790)
    
            fntString = New Font("Times New Roman", 12, FontStyle.Bold)
            e.Graphics.DrawString("Order Total:", fntString, 
                                      Brushes.Black, 420, 800)
            fntString = New Font("Times New Roman", 12, FontStyle.Regular)
            e.Graphics.DrawString(txtOrderTotal.Text, fntString, 
                              Brushes.Black, 640, 800, fmtString)
            e.Graphics.DrawLine(New Pen(Color.Black, 1), 
                                420, 820, 720, 820)
    End Sub

19. Return to the Order Processing form
20. From the Printing section of the Toolbox, click PrintDialog and click the form
21. In the Properties window, change its Name to dlgPrint
22. Still in the Properties windows, set its Document property to docPrint
23. Right-click the Order Processing form and click View Code
24. In the Class Name combo box, select btnPrint
25. In the Method name combo box, select Click and implement the event as follows:
    

    Private Sub btnPrintClick(ByVal sender As Object, 
                                   ByVal e As System.EventArgs) 
                                   Handles btnPrint.Click
        If dlgPrint.ShowDialog() = DialogResult.OK Then
            docPrint.Print()
        End If
    End Sub

26. Return to the Order Processing form
27. From the Printing section of the Toolbox, click PrintPreviewDialog and click the form
28. In the Properties window, change its (Name) to dlgPrintPreview
29. Still in the Properties windows, set its Document property to docPrint
30. Right-click the Order Processing form and click View Code
31. In the Class name combo box, select btnPrintPreview
32. In the Method name combo box, select Click and implement the event as follows:
    

    Private Sub btnPrintPreviewClick(ByVal sender As Object, 
                                          ByVal e As System.EventArgs) 
                                          Handles btnPrintPreview.Click
        dlgPrintPreview.ShowDialog()
    End Sub

33. In the Class name combo box, select btnNewRentalOrder
34. In the Method Name combo box, select Click and implement the event as follows:
    

    Private Sub btnNewRentalOrderClick(ByVal sender As Object, 
                                            ByVal e As System.EventArgs) 
                                            Handles btnNewRentalOrder.Click
            cbxEmployeeID.SelectedIndex = -1
            txtEmployeeName.Text = ""
            cbxCustomerID.SelectedIndex = -1
            txtCustomerName.Text = ""
            txtCustomerAddress.Text = ""
            txtCustomerCity.Text = ""
            cbxCustomerStates.Text = "DC"
            txtCustomerZIPCode.Text = ""
            cbxCarID.SelectedIndex = -1
            cbxCarConditions.SelectedIndex = 2
            txtMake.Text = ""
            txtModel.Text = ""
            txtCarYear.Text = ""
            cbxTankLevels.SelectedIndex = 0
            txtMileageStart.Text = "0"
            txtMileageEnd.Text = "0"
            dtpDateProcessed.Value = DateTime.Today
            dtpStartDate.Value = DateTime.Today
            dtpEndDate.Value = DateTime.Today
            txtDays.Text = "1"
            txtRateApplied.Text = "0.00"
            txtSubTotal.Text = "0.00"
            txtTaxAmount.Text = "0.00"
            txtOrderTotal.Text = "0.00"
            cbxOrderStatus.SelectedIndex = 0
    End Sub

35. In the Solution Explorer, right-click Form1.vb and click Rename
36. Type Central.vb and press Enter
37. Design the form as follows:
     

    Control Text Name Button Order Processing... btnOrderProcessing Button Customers... btnCustomers Button Car Editor... btnCarEditor Button Employees btnEmployees Button Close btnClose

38. Right-click the form and click View Code
39. Above the Public Class Central line, import the System.IO namespace
     

    Imports System.IO Public Class Central End Class

40. In the Class Name combo box, select (Central Events)
41. In the Method Name combo box, select Load and implement the event as follows:
     

    Imports System.IO Public Class Central Private Sub CentralLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load ' If this directory doesn't exist, create it Directory.CreateDirectory("C:\Bethesda Car Rental1") End Sub End Class

42. In the Class Name combo box, select btnOrderProcessing
43. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnOrderProcessingClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnOrderProcessing.Click Dim Order As OrderProcessing = New OrderProcessing Order.ShowDialog() End Sub

44. To add a new form to the project, in the Solution Explorer, right-click BethesdaCarRental2 -> Add -> Windows Form...
45. Set the Name to RentalRates and press Enter
46. 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
    colWeek}	Week}	Right

47. 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

48. Complete the design of the form as follows:
     
    
49. In the Solution Explorer, right-click OrderProcessing.vb and click View Code
50. In the Class Name combo box, select btn Rental Rates
51. In the Method Name combo box, select Click and implement its event as follows:
     

    Private Sub btnRentalRatesClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnRentalRates.Click Dim WindowRates As RentalRates = New RentalRates WindowRates.Show() End Sub

52. To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental2 -> Add -> Windows Form...
53. Set the Name to Employees and click Add
54. From the Data section of the Toolbox, click DataSet and click the form
55. Click Untyped Dataset and click OK
56. In the Properties window, change the following characteristics:
    DataSetName: Employees
    (Name): dsEmployees
57. Click Tables and click its button
58. Click Add and change the following characteristics:
    TableName: Employee
    (Name) tblEmployee
59. Click Columns and click its button
60. In the Columns Collection Editor, click Add change the characteristics as follows:
    ColumnName: EmployeeID
    (Name): colEmployeeID

1. While the EmployeeID member is selected, in the Properties list, double-click AutoIncrement to set its value to True
2. Click AutoIncrementSeed and type 1
3. Click Add continuously and create the following columns:
    

   AllowDBNull	ColumnName	(Name)	Expression
   False	EmployeeNumber	colEmployeeNumber
   	FirstName	colFirstName
   False	LastName	colLastName
   	FullName	colFullName	LastName + ', ' + FirstName
   	Title	colTitle

4. Click Close and click Close
5. Design the form as follows:
    

   Control Text Name Other Properties DataGridView   dgvEmployees DataSource: dsEmployees DataMember: Employee Button Close btnClose

   Data Grid Columns

   DataPropertyName HeaderText Width EmployeeID Empl ID 50 EmployeeNumber Empl # 65 FirstName First Name 70 LastName Last Name 70 FullName Full Name 120 Title   110

6. Right-click the form and click View Code
7. Above the Public Class Employees line, import the System.IO namespace
    

   Imports System.IO Public Class Employees End Class

8. In the Class Name combo box, select (Employees Events)
9. In the Method Name combo box, select Load and implement the event as follows:
    

   Imports System.IO Public Class Employees Private Sub EmployeesLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim Filename As String = "C:\Bethesda Car Rental1\employees.xml" If File.Exists(Filename) Then dsEmployees.ReadXml(Filename) End If End Sub End Class

10. In the Class Name combo box, select (Employees Events)
11. In the Method name combo box, select FormClosing and implement the event as follows:
     

    Private Sub EmployeesFormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing dsEmployees.WriteXml("C:\Bethesda Car Rental1\employees.xml") End Sub

12. In the Class Name combo box, select btnClose
13. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnCloseClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClose.Click Close() End Sub

14. In the Solution Explorer, right-click Central.vb and click View Code
15. In the Class Name combo box, select btnEmployees
16. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnEmployeesClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnEmployees.Click Dim frmEmployees As Employees = New Employees frmEmployees.ShowDialog() End Sub

17. Execute the application
18. On the Central form, click the Employees button
19. Create a few employees as follows:
     

    Employee #	First Name	Last Name	Title
    62-845	Patricia	Katts	General Manager
    92-303	Henry	Larson	Sales Representative
    25-947	Gertrude	Monay	Sales Representative
    73-947	Helene	Sandt	Intern
    40-508	Melanie	Karron	Sales Representative
    22-580	Ernest	Chisen	Sales Manager
    20-308	Melissa	Roberts	Administrative Assistant

20. Close the forms and return to your programming environment
21. To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental2 -> Add -> Windows Form...
22. Set the Name to Customers and click Add
23. From the Data section of the Toolbox, click DataSet and click the form
24. Click Untyped Dataset and click OK
25. In the Properties window, change the following characteristics:
    DataSetName: Customers
    (Name): dsCustomers
26. Click Tables and click its button
27. Click Add and change the following characteristics:
    TableName: Customer
    (Name) tblCustomer
28. Click Columns and click its button
29. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    CustomerID	colCustomerID	AutoIncrement: True AutoIncrementSeed: 1
    DrvLicNumber	colDrvLicNumber	AllowDBNull: False Unique: True
    FullName	colFullName	AllowDBNull: False
    Address	colAddress
    City	colCity
    State	colState
    ZIPCode	colZIPCode

30. Click Close and click Close
31. Design the form as follows:
     

    Control Text Name Other Properties DataGridView   dgvCustomers DataSource: dsCustomers DataMember: Customer Button Close btnClose

    Data Grid Columns

    DataPropertyName HeaderText Width CustomerID Cust ID 50 DrvLicNumber Drv Lic # 80 FullName Full Name   Address     City   80 State   45 ZIPCode ZIP Code 60

32. Right-click the form and click View Code
33. Above the Public Class Customers line, import the System.IO namespace
     

    Imports System.IO Public Class Customers End Class

34. In the Class Name combo box, select (Customers Events)
35. In the Method Name combo box, select Load and implement the event as follows:
     

    Imports System.IO Public Class Customers Private Sub CustomersLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim Filename As String = "C:\Bethesda Car Rental1\customers.xml" If File.Exists(Filename) Then dsCustomers.ReadXml(Filename) End If End Sub End Class

36. In the Method Name combo box, select FormClosing and implement the event as follows:
     

    Private Sub CustomersFormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing dsCustomers.WriteXml("C:\Bethesda Car Rental1\customers.xml") End Sub

37. In the Class name combo box, select btnClose
38. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnCloseClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClose.Click Close() End Sub

39. In the Solution Explorer, right-click Central.vb and click View Code
40. In the Class name combo box, select btnCustomers 
41. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnCustomersClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCustomers.Click Dim frmCustomers As Customers = New Customers frmCustomers.ShowDialog() End Sub

42. Execute the application
43. Click the Customers button and create a few customers as follows:
     

    Driver's Lic. #	State	Full Name	Address	City	ZIP Code
    M-505-862-575	MD	Lynda Melman	4277 Jamison Avenue	Silver Spring	20904
    379-82-7397	DC	John Villard	108 Hacken Rd NE	Washington	20012
    J-938-928-274	MD	Chris Young	8522 Aulage Street	Rockville	20852
    497-22-0614	PA	Pamela Ulmreck	12075 Famina Rd	Blain	17006
    922-71-8395	VA	Helene Kapsco	806 Hyena Drive	Alexandria	22231
    C-374-830-422	MD	Hermine Crasson	6255 Old Georgia Ave	Silver Spring	20910
    836-55-2279	NY	Alan Pastore	4228 Talion Street	Amherst	14228
    397-59-7487	TN	Phillis Buster	724 Cranston Circle	Knoxville	37919
    115-80-2957	FL	Elmus Krazucki	808 Rasters Ave	Orlando	32810
    294-90-7744	VA	Helena Weniack	10448 Great Pollard Hwy	Arlington	22232

44. Close the Customers form
45. To add a new form to the application, in the Solution Explorer, right-click BethesdaCarRental2 -> Add -> Windows Form...
46. Set the Name to CarEditor and click Add
47. Design the form as follows: 
     

    Control Text Name Other Properties Label Text #     TextBox   txtTagNumber   Label Make:     TextBox   txtMake   Label Model:     TextBox   txtModel   Label Year:     TextBox   txtYear   Label Category:     ComboBox   cboCategories DropDownStyle: DropDownList Items: Economy Compact Standard Full Size Mini Van SUV Truck Van PictureBox   pbxCar SizeMode: Zoom CheckBox CD Player chkCDPlayer CheckAlign: MiddleRight CheckBox DVD Player chkDVDPlayer CheckAlign: MiddleRight Button Select Car Picture... btnSelectPicture   CheckBox Available chkAvailable CheckAlign: MiddleRight Label Picture Name lblPictureName   Button Submit btnSubmit   Button Close btnClose 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

48. Right-click the form and click View Code
49. Above the Public Class CarEditor line, import the System.IO namespace
     

    Imports System.IO Public Class CarEditor End Class

50. In the Class Name combo box, select btnSelectPicture
51. In the Method Name combo box, select Click and implement the event as follows:
     

    Imports System.IO Public Class CarEditor Private Sub btnSelectPictureClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSelectPicture.Click If dlgPicture.ShowDialog() = DialogResult.OK Then lblPictureName.Text = dlgPicture.FileName pbxCar.Image = Image.FromFile(lblPictureName.Text) End If End Sub End Class

52. Return to the Car Editor form
53. From the Data section of the Toolbox, click DataSet and click the form
54. Click Untyped Dataset and click OK
55. In the Properties window, change the following characteristics:
    DataSetName: Cars
    (Name): dsCars
56. Click Tables and click its button
57. Click Add and change the following characteristics:
    TableName: Car
    (Name) tblCar
58. Click Columns and click its button
59. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    CarID	colCarID	AutoIncrement: True AutoIncrementSeed: 1
    TagNumber	colTagNumber	AllowDBNull: False Unique: True
    Make	colMake
    Model	colModel
    Year	colYear	DataType: System.UInt16
    Category	colCategory
    CDPlayer	colCDPlayer	DataType: System.Boolean
    DVDPlayer	colDVDPlayer	DataType: System.Boolean
    Available	colAvailable	DataType: System.Boolean

60. Click Close and click Close
61. Right-click the form and click View Code
62. In the Class name com box, select btnSubmit
63. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnSubmitClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSubmit.Click If txtTagNumber.Text.Length = 0 Then MsgBox("You must enter the car's tag number") Exit Sub End If If txtMake.Text.Length = 0 Then MsgBox("You must specify the car's manufacturer") Exit Sub End If If txtModel.Text.Length = 0 Then MsgBox("You must enter the model of the car") Exit Sub End If If txtYear.Text.Length = 0 Then MsgBox("You must enter the year of the car") Exit Sub End If Dim CarRecord As DataRow = tblCar.NewRow() CarRecord("TagNumber") = txtTagNumber.Text CarRecord("Make") = txtMake.Text CarRecord("Model") = txtModel.Text CarRecord("CarYear") = txtYear.Text CarRecord("Category") = cbxCategories.Text CarRecord("CDPlayer") = chkCDPlayer.Checked CarRecord("DVDPlayer") = chkDVDPlayer.Checked CarRecord("Available") = chkAvailable.Checked tblCar.Rows.Add(CarRecord) dsCars.WriteXml("C:\Bethesda Car Rental1\cars.xml") If lblPictureName.Text.Length <> 0 Then Dim flePicture As FileInfo = New FileInfo(lblPictureName.Text) flePicture.CopyTo("C:\Bethesda Car Rental1\" & txtTagNumber.Text & flePicture.Extension) End If txtTagNumber.Text = "" txtMake.Text = "" txtModel.Text = "" txtYear.Text = "" cbxCategories.Text = "Economy" chkCDPlayer.Checked = False chkDVDPlayer.Checked = False chkAvailable.Checked = False lblPictureName.Text = "." pbxCar.Image = Nothing End Sub

64. In the Class name combo box, select btnClose
65. In the Method name combo box, select Click and implement the event as follows:
     

    Private Sub btnCloseClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClose.Click Close() End Sub

66. In the Solution Explorer, right-click Central.vb and click View Code
67. In the Class name combo box, select btn Car Editor
68. In the Method name combo box, select Click and implement the as follows:
     

    Private Sub btnCarEditorClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCarEditor.Click Dim Editor As CarEditor = New CarEditor Editor.ShowDialog() End Sub

69. Copy the following pictures to any folder somewhere on your computer:
     

    BMW: 335i	Chevrolet Avalanche
    Honda Accord	Mazda Miata
    Chevrolet Aveo	Ford E150XL
    Buick Lacrosse	Honda Civic
    Ford F-150	Mazda Mazda5
    Volvo S40	Land Rover LR3

70. Execute the application
71. Click the Car Editor button and create the cars
     
72. Close the Car Editor form and return to your programming environment
73. In the Solution Explorer, double-click OrderProcessing.vb
74. From the Data section of the Toolbox, click DataSet and click the form
75. Click Untyped Dataset and click OK
76. In the Properties window, change the following characteristics:
    DataSetName: RentalOrders
    (Name): dsRentalOrders
77. Click Tables and click its button
78. Click Add and change the following characteristics:
    TableName: RentalOrder
    (Name) tblRentalOrder
79. Click Columns and click its ellipsis button
80. In the Columns Collection Editor, click Add twice and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    RentalOrderID	colRentalOrderID	AutoIncrement: True AutoIncrementSeed: 1000
    DateProcessed	colDateProcessed	DataType: System.DateTime

81. Click Close

1. While the RentalOrder table is still selected in the Members list, in the Properties list, click Constraints and click its button
2. In the Constraints Collection Editor, click Add -> Unique Constraint
    
   
3. Set the Name to PKRentalOrders
4. Click the check box of RentalOrderID and click the Primary Key check box
    
   
5. Click OK and click Close
6. Click Columns and create the following columns:
    

   ColumnName	(Name)	Other Properties
   RentalOrderID	colRentalOrderID
   DateProcessed	colDateProcessed
   EmployeeID	colEmplID	DataType: System.Int32
   EmployeeName	colEmployeeName
   CustomerID	colCustID	DataType: System.Int32
   CustomerName	colCustomerName
   CustomerAddress	colCustomerAddress
   CustomerCity	colCustomerCity
   CustomerState	colCustomerState
   CustomerZIPCode	colCustomerZIPCode
   CarID	colVehicleID	DataType: System.Int32
   Make	colCarMake
   Model	colCarModel
   Year	colCarYear	DataType: System.UInt16
   Condition	colCarCondition
   TankLevel	colTankLevel
   MileageStart	colMileageStart	DataType: System.UInt32
   Mileage}	colMileage}	DataType: System.UInt32
   RentStartDate	colRentStartDate	DataType: System.DateTime
   RendependDate	colRendependDate	DataType: System.DateTime
   Days	colDays	DataType: System.UInt16
   RateApplied	colRateApplied	DataType: System.Double
   SubTotal	colSubTotal	DataType: System.Double
   TaxRate	colTaxRate	DataType: System.Double
   TaxAmount	colTaxAmount	DataType: System.Double
   OrderTotal	colOrderTotal	DataType: System.Double
   OrderStatus	colOrderStatus

7. Click Close
8. While the RentalOrder table is selected, in the RentalOder Properties list, click PrimaryKey and click the arrow of its combo box.
   Notice the check box on RentalOrderID
    
   
9. In the Tables Collection Editor, click Add and change the following characteristics:
   TableName: Car
   (Name) tblCar
10. Click Columns and click its button
11. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    CarID	colCarID	AutoIncrement: True AutoIncrementSeed: 1
    TagNumber	colTagNumber	AllowDBNull: False Unique: True
    Make	colMake
    Model	colModel
    Year	colYear	DataType: System.UInt16
    Category	colCategory
    CDPlayer	colCDPlayer	DataType: System.Boolean
    DVDPlayer	colDVDPlayer	DataType: System.Boolean
    Available	colAvailable	DataType: System.Boolean

12. Click Close
13. While the Car table is selected, in the Properties list, click Constraints and its button
14. In the Constraints Collection Editor, if Constraint1 is selected, click Edit (otherwise, click Add -> Unique Constraint)
15. Set the Name to PKCars
16. Click the check box of CarID and click the Primary Key check box:
     
    
17. Click OK and click Close
18. In the Tables Collection Editor, click Add and change the following characteristics:
    TableName: Customer
    (Name) tblCustomer
19. Click Columns and click its button
20. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    CustomerID	colCustomerID	AutoIncrement: True AutoIncrementSeed: 1
    DrvLicNumber	colDrvLicNumber	AllowDBNull: False Unique: True
    FullName	colFullName	AllowDBNull: False
    Address	colAddress
    City	colCity
    State	colState
    ZIPCode	colZIPCode

21. Click Close
22. Click Constraints and click its button
23. In the Constraints Collection Editor, if Constraint1 is selected, click Edit (otherwise, click Add -> Unique Constraint)
24. Set the Name to PKCustomers
25. Click the check box of CustomerID and click the Primary Key check box (clear any other check box)
26. Click OK and click Close
27. In the Tables Collection Editor, click Add and change the following characteristics:
    TableName: Employee
    (Name) tblEmployee
28. Click Columns and click its button
29. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Additional Properties
    EmployeeID	colEmployeeID	AutoIncrement: True AutoIncrementSeed: 1
    EmployeeNumber	colEmployeeNumber	AllowDBNull: False Unique: True
    FirstName	colFirstName	AllowDBNull: False
    LastName	colLastName
    FullName	colEmplFullName
    Title	colTitle

30. Click Close
31. Click Constraints and click its button
32. In the Constraints Collection Editor, if Constraint1 is selected, click Edit (otherwise, click Add -> Unique Constraint)
33. Set the Name to PKEmployees
34. Click the check box of EmployeeID and click the Primary Key check box (clear any other check box)
35. Click OK and click Close
36. Right-click the form and click View Code

1. In the Class Name combo box, select (OrderProcessing Events)
2. In the Method Name combo box, select Load event and implement the event as follows:
    

   Private Sub OrderProcessingLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim Filename As String = "C:\Bethesda Car Rental\employees.xml" If File.Exists(Filename) Then dsRentalOrders.ReadXml(Filename) End If Filename = "C:\Bethesda Car Rental\customers.xml" If File.Exists(Filename) Then dsRentalOrders.ReadXml(Filename) End If Filename = "C:\Bethesda Car Rental\cars.xml" If File.Exists(Filename) Then dsRentalOrders.ReadXml(Filename) End If End Sub

3. Return to the Order Processing form and click the Employee # combo box
4. In the Properties window, change the following characteristics:
   DataSource: dsRentalOrders
   DisplayMember: Employee.EmployeeNumber
5. Right-click the form and click View Code
6. In the Class Name combo box, select cbxEmployeeID
7. In the Method Name combo box, select SelectedIndexChanged and implement the event as follows:
    

   Private Sub cbxEmployeeIDSelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbxCustomerID.SelectedIndexChanged For Each Record As DataRow In tblEmployee.Rows If cbxEmployeeID.Text = Record("EmployeeNumber") Then txtEmployeeName.Text = Record("FullName") End If Next End Sub

8. Return to the form and click the Driver's Lic # combo box
9. In the Properties window, change the following characteristics:
   DataSource: dsRentalOrders
   DisplayMember: Customer.DrvLicNumber
10. Right-click the form and click View Code
11. In the Class Name combo box, select cbxCustomerID
12. In the Method Name combo box, select SelectedIndexChanged and implement the event as follows:
      

    Private Sub cbxCustomerIDSelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbxCustomerID.SelectedIndexChanged For Each Record As DataRow In tblCustomer.Rows If cbxCustomerID.Text = Record("DrvLicNumber") Then txtCustomerName.Text = Record("FullName") txtCustomerAddress.Text = Record("Address") txtCustomerCity.Text = Record("City") cbxCustomerStates.Text = Record("State") txtCustomerZIPCode.Text = Record("ZIPCode") End If Next End Sub

13. Return to the form and click the Tag Number combo box
14. In the Properties window, change the following characteristics:
    DataSource: dsRentalOrders
    DisplayMember: Car.TagNumber
15. Right-click the form and click View Code
16. In the Class Name combo box, select cbxCarID
17. In the Method Name combo box, select SelectedIndexChanged and implement the event as follows:
     

    Private Sub cbxCarIDSelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbxCarID.SelectedIndexChanged For Each Record As DataRow In tblCar.Rows If cbxCarID.Text = Record("TagNumber") Then txtMake.Text = Record("Make") txtModel.Text = Record("Model") txtCarYear.Text = Record("Year") End If Next End Sub

18. Return to the OrderProcessing form
19. From the Data section of the Toolbox, click DataSet and click the form
20. Click Untyped Dataset and click OK
21. In the Properties window, change the following characteristics:
    DataSetName: OrderProcessing
    (Name):dsOrderProcessing
22. Click the ellipsis button of the Tables field
23. In the Tables Collection Editor, click Add and change the characteristics as follows:
    TableName: RentalOrder
    (Name): tblRental
24. Click the ellipsis button of the Columns field
25. In the Columns Collection Editor, click Add continuously and create the following columns:
     

    ColumnName	(Name)	Other Properties
    ReceiptNumber	colReceiptNumber	AutoIncrement: True AutoIncrementSeed: 1001
    DateProcessed	colProcessedDate
    OrderStatus	colStatus
    EmployeeNumber	colEmplNumber
    EmployeeName	colEmplName
    CustomerDrvLicNbr	colDrvLicNbr
    CustomerName	colCustName
    CustomerAddress	colCustAddress
    CustomerCity	colCustCity
    CustomerState	colCustState
    CustomerZIPCode	colCustZIPCode
    CarTagNumber	colCarTagNumber
    CarMake	colMake
    CarModel	colVehicleModel
    CarYear	colVehicleYear
    CarCondition	colCondition
    CarTankLevel	colCarTankLevel
    MileageStart	colCarMileageStart
    MileageEnd	colCarMileageEnd
    RentStartDate	colStartDate
    RendependDate	colEndDate
    TotalDays	colTotalDays
    RateApplied	colAppliedRate
    SubTotal	colTotalSub
    TaxRate	colRateTax
    TaxAmount	colAmountTax
    OrderTotal	colTotalOrder

26. Click Close and click Close
27. Right-click t he form and click View Code
28. In the Class Name combo box, select btnSave
29. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnSaveClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click ' Don't save this rental order if we don't ' know who processed it If cbxEmployeeID.SelectedIndex < 0 Then MsgBox("You must select the employee number or " & "the clerk who processed this order.") Exit Sub End If ' Don't save this rental order if we don't ' know who is renting the car If cbxCustomerID.SelectedIndex < 0 Then MsgBox("You must select the driver's license number " & "of the customer who is renting the car") Exit Sub End If ' Don't save the rental order if we don't ' know what car is being rented If cbxCarID.SelectedIndex < 0 Then MsgBox("You must select the tag number " & "of the car that is being rented") Exit Sub End If ' This variable will allow us to know whether ' we are only updating a rental order Dim Found As Boolean = False ' This is the XML file that holds the rental orders Dim Filename As String = "C:\Bethesda Car Rental1\RentalOrders.xml" ' This is the stream that holds the file Dim bcrStream As FileStream = New FileStream(Filename, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite) ' Check the rental orders For Each Record As DataRow In tblRental.Rows ' Find out if there is already a rental ' order with the current receipt number If Record("ReceiptNumber") = txtReceiptNumber.Text Then ' Since the rental order was found, make note Found = True ' Get ready to update the rental order Record("DateProcessed") = dtpDateProcessed.Value.ToString("d") Record("EmployeeNumber") = cbxEmployeeID.Text Record("EmployeeName") = txtEmployeeName.Text Record("CustomerDrvLicNbr") = cbxCustomerID.Text Record("CustomerName") = txtCustomerName.Text Record("CustomerAddress") = txtCustomerAddress.Text Record("CustomerCity") = txtCustomerCity.Text Record("CustomerState") = cbxCustomerStates.Text Record("CustomerZIPCode") = txtCustomerZIPCode.Text Record("CarTagNumber") = cbxCarID.Text Record("CarMake") = txtMake.Text Record("CarModel") = txtModel.Text Record("CarYear") = txtCarYear.Text Record("CarCondition") = cbxCarConditions.Text Record("CarTankLevel") = cbxTankLevels.Text Record("MileageStart") = txtMileageStart.Text Record("Mileage}") = txtMileageEnd.Text Record("RentStartDate") = dtpStartDate.Value.ToString("d") Record("RendependDate") = dtpEndDate.Value.ToString("d") Record("TotalDays") = txtDays.Text Record("RateApplied") = txtRateApplied.Text Record("SubTotal") = txtSubTotal.Text Record("TaxRate") = txtTaxRate.Text Record("TaxAmount") = txtTaxAmount.Text Record("OrderTotal") = txtOrderTotal.Text Record("OrderStatus") = cbxOrderStatus.Text ' STOP!!! Exit For End If Next ' If the receipt number was not found, ' then prepare to create a new rental order If Found = False Then Dim Record As DataRow = tblRental.NewRow() Record("DateProcessed") = dtpDateProcessed.Value.ToString("d") Record("EmployeeNumber") = cbxEmployeeID.Text Record("EmployeeName") = txtEmployeeName.Text Record("CustomerDrvLicNbr") = cbxCustomerID.Text Record("CustomerName") = txtCustomerName.Text Record("CustomerAddress") = txtCustomerAddress.Text Record("CustomerCity") = txtCustomerCity.Text Record("CustomerState") = cbxCustomerStates.Text Record("CustomerZIPCode") = txtCustomerZIPCode.Text Record("CarTagNumber") = cbxCarID.Text Record("CarMake") = txtMake.Text Record("CarModel") = txtModel.Text Record("CarYear") = txtCarYear.Text Record("CarCondition") = cbxCarConditions.Text Record("CarTankLevel") = cbxTankLevels.Text Record("MileageStart") = txtMileageStart.Text Record("Mileage}") = txtMileageEnd.Text Record("RentStartDate") = dtpStartDate.Value.ToString("d") Record("RendependDate") = dtpEndDate.Value.ToString("d") Record("TotalDays") = txtDays.Text Record("RateApplied") = txtRateApplied.Text Record("SubTotal") = txtSubTotal.Text Record("TaxRate") = txtTaxRate.Text Record("TaxAmount") = txtTaxAmount.Text Record("OrderTotal") = txtOrderTotal.Text Record("OrderStatus") = cbxOrderStatus.Text tblRental.Rows.Add(Record) End If ' Now that the rental order is ready, ... Try ' ... save it dsOrderProcessing.WriteXml(bcrStream) Finally bcrStream.Close() End Try End Sub

30. In the Class Name combo box, select btnOpen
31. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnOpenClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnOpen.Click Dim Found As Boolean = False Try Dim Filename As String = "C:\Bethesda Car Rental1\RentalOrders.xml" If File.Exists(Filename) Then dsOrderProcessing.ReadXml(Filename) For Each Record As DataRow In tblRental.Rows If Record("ReceiptNumber") = txtReceiptNumber.Text Then Found = True dtpDateProcessed.Value = DateTime.Parse(Record("DateProcessed")) cbxEmployeeID.Text = Record("EmployeeNumber") txtEmployeeName.Text = Record("EmployeeName") cbxCustomerID.Text = Record("CustomerDrvLicNbr") txtCustomerName.Text = Record("CustomerName") txtCustomerAddress.Text = Record("CustomerAddress") txtCustomerCity.Text = Record("CustomerCity") cbxCustomerStates.Text = Record("CustomerState") txtCustomerZIPCode.Text = Record("CustomerZIPCode") cbxCarID.Text = Record("CarTagNumber") txtMake.Text = Record("CarMake") txtModel.Text = Record("CarModel") txtCarYear.Text = Record("CarYear") cbxCarConditions.Text = Record("CarCondition") cbxTankLevels.Text = Record("CarTankLevel") txtMileageStart.Text = Record("MileageStart") txtMileageEnd.Text = Record("MileageEnd") dtpStartDate.Value = DateTime.Parse(Record("RentStartDate")) dtpEndDate.Value = DateTime.Parse(Record("RendependDate")) txtDays.Text = Record("TotalDays") txtRateApplied.Text = Record("RateApplied") txtSubTotal.Text = Record("SubTotal") txtTaxRate.Text = Record("TaxRate") txtTaxAmount.Text = Record("TaxAmount") txtOrderTotal.Text = Record("OrderTotal") cbxOrderStatus.Text = Record("OrderStatus") Exit For End If Next Else MsgBox("There is no cleaning order to open") End If Catch Exc As ConstraintException End Try If Found = False Then MsgBox("There is no rental order with that receipt number") End If End Sub

32. In the Class Name combo box, select btnClose
33. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnCloseClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClose.Click Close End Sub

34. In the Solution Explorer, right-click Central.vb and click View Code
35. In the Class Name combo box, select btnClose
36. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub btnCloseClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClose.Click End End Sub

37. Execute the application