validaspmortgage.aspx.vb

Programming Web and Desktop Applications in ADO .NET and ASP .NET

Public Class WebForm1
    Inherits System.Web.UI.Page
    Protected WithEvents Label1 As System.Web.UI.WebControls.Label
    Protected WithEvents lblTotalPayment As System.Web.UI.WebControls.Label
    Protected WithEvents lblYears As System.Web.UI.WebControls.Label
    Protected WithEvents txtInterestRate As System.Web.UI.WebControls.TextBox
    Protected WithEvents Label2 As System.Web.UI.WebControls.Label
    Protected WithEvents Label3 As System.Web.UI.WebControls.Label
    Protected WithEvents Label4 As System.Web.UI.WebControls.Label
    Protected WithEvents txtPrincipal As System.Web.UI.WebControls.TextBox
    Protected WithEvents ddlYears As System.Web.UI.WebControls.DropDownList
    Protected WithEvents chkTotalPmt As System.Web.UI.WebControls.CheckBox
    Protected WithEvents lblMonthPayment As System.Web.UI.WebControls.Label
    Protected WithEvents btnCompute As System.Web.UI.WebControls.Button
    Protected WithEvents ReqdFldValdtrtxtPrincipal As System.Web.UI.WebControls.RequiredFieldValidator
    Protected WithEvents RngValdtrtxtPrincipal As System.Web.UI.WebControls.RangeValidator
    Protected WithEvents RegExpValdtrtxtInterestRate As System.Web.UI.WebControls.RegularExpressionValidator
    Protected WithEvents ReqdFldValdtrtxtInterestRate As System.Web.UI.WebControls.RequiredFieldValidator
    Protected WithEvents CstmVldtrddlYears As System.Web.UI.WebControls.CustomValidator

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: This method call is required by the Web Form Designer
        'Do not modify it using the code editor.
        InitializeComponent()
    End Sub

#End Region

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        If Not Page.IsPostBack Then
            lblMonthPayment.Text = ""
            lblTotalPayment.Text = ""
            lblYears.Text = ""
        End If
    End Sub

    Private Sub ddlYears_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlYears.SelectedIndexChanged
        'Display Period Selected
        lblYears.Text = "Loan Duration " + ddlYears.SelectedItem.Text
    End Sub

    Private Sub btnCompute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCompute.Click

        'Compute Mortgage and Display Results
        Dim sngPrincipal, sngInterest, sngPayment As Single
        Dim intYears As Integer

        If Page.IsValid Then
            sngPrincipal = CSng(txtPrincipal.Text)
            sngInterest = CSng(txtInterestRate.Text) / 1200
            Select Case ddlYears.SelectedItem.Text
                Case "10 Years"
                    intYears = 10
                Case "15 Years"
                    intYears = 15
                Case "20 Years"
                    intYears = 20
                Case "25 Years"
                    intYears = 25
                Case "30 Years"
                    intYears = 30
            End Select

            intYears = intYears * 12

            sngPayment = sngPrincipal * (sngInterest _
            / (1 - (1 + sngInterest) ^ -intYears))

            lblMonthPayment.Text = "Monthly Payments = " & _
            FormatCurrency(sngPayment)

            lblTotalPayment.Text = "Total Payments " & _
            FormatCurrency(sngPayment * intYears)

            'Display/Hide Total Payment
            lblTotalPayment.Visible = chkTotalPmt.Checked
        End If
    End Sub

    Private Sub chkTotalPmt_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkTotalPmt.CheckedChanged
        'Show/Hide Total Payment Result
        lblTotalPayment.Visible = chkTotalPmt.Checked
    End Sub

    Private Sub CstmVldtrddlYears_ServerValidate(ByVal source As System.Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CstmVldtrddlYears.ServerValidate
        'Validate DropdownList Control input
        If args.Value = "Select Duration" Then
            args.IsValid = False
        Else
            args.IsValid = True
        End If
    End Sub
End Class