Question

一道VB 程序题，请求帮忙。要详细程序哦！

某航空公司规定在7~9月份，如果订票数超过20张，则票价优惠15%，如果超过10张则票价优惠5%，在1~5月份、10月份和11月份，如果订票数超过20张，则票价优惠25%，如果超过10张，则票价优惠15%。从窗体文本框中输入票价、月份以及订票数，并显示出所需金额。

Answer 1

Imports System
Imports System.Windows.Forms

Public Class Ticket
    Dim InteQuantity, DateMonth As Integer                      '数量与日期变量
    Dim DblPrice, DblTotal, DblDiscount, DblRates As Double     '单价、合计金额、优惠比例及优惠后金额变量

    Private Sub Ticket_Load(sender As Object, e As EventArgs) Handles Me.Load
        Me.DateTimePicker1.Focus()
    End Sub

    Private Sub DateTimePicker1_CloseUp(sender As Object, e As EventArgs) Handles DateTimePicker1.CloseUp
        DateMonth = Me.DateTimePicker1.Value.Month               '取开始日期的月份
        Me.TextBox1.Focus()
    End Sub

    Private Sub TextBox1_LostFocus(sender As Object, e As EventArgs) Handles TextBox1.LostFocus
        Dim strMsg As String = "输入有误，必须输入正整数，其他输入将会四舍五入！"
        If Trim(Me.TextBox1.Text) <> "" Then
            InteQuantity = Trim(CInt(Me.TextBox1.Text))
            If Not IsNumeric(InteQuantity) Then
                MsgBox(strMsg)
                Me.TextBox1.Text = ""
                Me.TextBox1.Focus()
            ElseIf InteQuantity < 0 Then
                MsgBox(strMsg)
                Me.TextBox1.Text = ""
                Me.TextBox1.Focus()
            Else
                Me.TextBox2.Focus()
            End If
        Else
            Me.TextBox1.Focus()
        End If
    End Sub

    Private Sub TextBox2_LostFocus(sender As Object, e As EventArgs) Handles TextBox2.LostFocus
        Dim strMsg As String = "输入有误，必须输入数字！"
        If Trim(Me.TextBox2.Text) <> "" Then
            DblPrice = Trim(CDbl(Me.TextBox2.Text))
            If Not IsNumeric(DblPrice) Then
                MsgBox(strMsg)
                Me.TextBox2.Text = ""
                Me.TextBox2.Focus()
            End If
        Else
            Me.TextBox2.Focus()
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        DblTotal = InteQuantity * DblPrice      '计算未优惠合计金额
        DblDiscount = 0
        Select Case DateMonth
            Case DateMonth <= 5 And DateMonth = 10 And DateMonth = 11
                If InteQuantity > 10 And InteQuantity <= 20 Then DblDiscount = 0.15
                If InteQuantity > 20 Then DblDiscount = 0.25
            Case DateMonth >= 7 And DateMonth <= 9
                If InteQuantity > 10 And InteQuantity <= 20 Then DblDiscount = 0.05
                If InteQuantity > 20 Then DblDiscount = 0.15
        End Select

        DblRates = InteQuantity * DblPrice * (1 - DblDiscount)    '计算优惠后合计金额

        Me.TextBox3.Text = DblTotal             '显示合计金额
        Me.TextBox4.Text = DblRates             '显示优惠后的合计金额
        Me.Label10.ForeColor = Color.Red
        If DblRates = 0 Then
            Me.Label10.Text = "注：您本次订票未享受优惠"
        Else
            Me.Label10.Text = "注：您本次订票共计享受" & Chr(13) & "优惠：" & DblTotal - DblRates & "元。" & Chr(13) & "优惠比例为" & DblDiscount * 100 & "%"
        End If

    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        DblTotal = 0                            '部分变量归零，避免二次输入时计算错误
        DblDiscount = 0
        DblRates = 0
        Me.DateTimePicker1.Value = Now
        Me.DateTimePicker1.Focus()
        Me.TextBox1.Text = ""
        Me.TextBox2.Text = ""
        Me.TextBox3.Text = ""
        Me.TextBox4.Text = ""
        Me.Label10.Text = ""
    End Sub
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        End
    End Sub

End Class

匆匆忙忙写的，未作详细的调试，在VB.Net2012上运行通过，未出错，可能还需要作此些小的调整，供你参考吧！