'学习心得
 
'运算符的优先级
 
'变量名的制定：g（是否是全局）+数据类型+变量=变量名；gdblName
 
' AcceptButton Property of the Form specifies this button.When the user press the Enter key or clicks the default button on a form that has the AcceptButton property set.
 
'
 
 
 
'MonthlyPayment = (InterestRate*(1+InterestRate)^NumberOfPayments)/((1+InterestRate)^NumberOfPayments-1)*LoanAmount 这个在   “Pmt Founction ”  里面有
 
'Format Function 将日期，时间等转换成专用的格式
 
 
 
 
 
Option Strict On
 
Public Class Form1
 
    'Purpose:       This project calculates the monthly payment:
 
    '               a loan based on loan amount,interest rate(利率),'               
 
 
 
    Dim gdblMonths As Double = 60.0
 
    Const MaximumLoanAllowed As Integer = 25000
 
 
 
 
 
 
 
    Private Sub Form1_Load(ByVal sender As Object,ByVal e As System.EventArgs) Handles Me.Load
 
        nudLoanAmount.Maximum = MaximumLoanAllowed
 
    End Sub
 
 
 
    Private Sub btnReset_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles btnReset.Click
 
        nudLoanAmount.Value = 0
 
        nudRate.Value = 5
 
        radFiveYears.Checked = True
 
        txtMonthlyPayment.Text = "$0.00"
 
    End Sub
 
 
 
    Private Sub radTwoYears_CheckedChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles radTwoYears.CheckedChanged
 
        gdblMonths = 24.0
 
    End Sub
 
 
 
    Private Sub radFiveYears_CheckedChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles radFiveYears.CheckedChanged
 
        gdblMonths = 12.0 * 5
 
    End Sub
 
 
 
    Private Sub radSixYears_CheckedChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles radSixYears.CheckedChanged
 
        gdblMonths = 12.0 * 6
 
    End Sub
 
 
 
    Private Sub btnComputePayment_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles btnComputePayment.Click
 
        Dim dblRate,dblMonths,dblPayment As Double
 
        Dim dblLoanAmount As Double,strPayment As String
 
        dblRate = (Convert.ToDouble(nudRate.Value) / 100.0) / 12.0
 
        dblLoanAmount = Convert.ToDouble(nudLoanAmount.Value)
 
        dblPayment = Pmt(dblRate,gdblMonths,-dblLoanAmount)
 
        strPayment = Format(dblPayment,"c")
 
        'strPayment = dblPayment.ToString        ' Or use  " convert.tostring(dblPayment) "
 
        txtMonthlyPayment.Text = strPayment        '显示的是本机的现金符号， 如需更改请用 globlization.currentinfo
 
    End Sub
 
End Class