Question

我是VB的新手，并且在课堂作业方面遇到了一些麻烦。基本上它应该采取发票小计 - 找到折扣百分比并给出实际总数。我似乎无法让我的类访问用户输入的文本框，它只是继续返回0。这也是一个家庭作业...我不是只是要求答案的一些提示，因为我真的不知所措，无法弄清楚这一点!!!

这是我点击按钮事件的代码：

Public Sub btnCalc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalc.Click
    'If txbxSubtotal.Text >= 500 Then
    '   discountpercent = 0.2
    'ElseIf txbxSubtotal.Text >= 250 And txbxSubtotal.Text < 500 Then
    '   discountpercent = 0.15
    'ElseIf txbxSubtotal.Text >= 100 And txbxSubtotal.Text < 250 Then
    '   discountpercent = 0.1
    'Else
    '   discountpercent = 0
    'End If
    'discountAmount = txbxSubtotal.Text * discountpercent
    'total = txbxSubtotal.Text - discountAmount
    Dim myinvoice As New Getinvoice
    myinvoice.setAmount(total = Convert.ToDecimal(txbxSubtotal.Text))
    total = txbxSubtotal.Text
    MessageBox.Show(myinvoice.getdiscountAmount)
    MessageBox.Show(myinvoice.getAmount)
End Sub
End Class

这是我班上的代码：

Public Class Getinvoice

    Private subtotal As Decimal
    Private discount As Decimal
    Private discountAmount As Decimal
    Private discountpercent As Decimal
    Private amount As Decimal

    Public Sub setAmount(ByVal total As Decimal)
        amount = total
    End Sub

    Public Function getAmount()
        Return amount
    End Function

    Public Sub setdiscountPercent(ByVal discPcnt As Decimal)
        discountAmount = discPcnt

        If amount >= 500 Then
            discountpercent = 0.2
        ElseIf amount >= 250 And amount < 500 Then
            discountpercent = 0.15
        ElseIf amount >= 100 And amount < 250 Then
            discountpercent = 0.1
        Else
            discountpercent = 0
        End If
    End Sub

    Public Function getdiscountAmount()
        Return discountpercent
    End Function

End Class

Answer 1

您从未致电

setdiscountPercent(ByVal discPcnt As Decimal)

所以从不设置discountpercent。这就是为什么你得到0;

编辑：

Public Sub setdiscountPercent(ByVal discPcnt As Decimal)
    discountAmount = discPcnt

    If amount >= 500 Then
        discountpercent = 0.2
    ElseIf amount >= 250 And amount < 500 Then
        discountpercent = 0.15
    ElseIf amount >= 100 And amount < 250 Then
        discountpercent = 0.1
    Else
        discountpercent = 0
    End If
End Sub

这是你的代码。看一下您在此方法discountAmount = discPcnt

中设置的内容

但是，在您发布的代码中，您永远不会致电setdiscountPercent(ByVal discPcnt As Decimal)

因此，discountAmount和discountpercent永远不会设置为任何值。这就是问题的来源。

无法访问课程中的文本框输入

1 个答案: