vb.net - VB 2010 中的计算问题

Question

我无法弄清楚这段代码的问题出在哪里。我的计算一直运行良好，直到最后一种情况 (CASE IS > 8)，该情况连续返回 0.00 作为结果。我确信像我这样的新手由于缺乏经验而缺少一些小东西。感谢您的帮助!

' Declaration of Variable

Convert.ToInt32(txtAttending.Text)
Dim decAttending = txtAttending.Text

If IsNumeric(txtAttending.Text) And txtAttending.Text <= 16 Then
    Select Case txtAttending.Text
        Case Is = 1
            decCost = 695 * decAttending
        Case 2 To 4
            decCost = 545 * decAttending
        Case 5 To 8
            decCost = 480 * decAttending
        Case Is > 8
            decCost = 395 * decAttending
    End Select
Else
    MsgBox("Please double check that your input is a number not greater than 16", , "Input Error")

End If

If radYes.Checked = True Then
    decFinalCost = (decCost - (decCost * 0.15))
    lblRepeatDiscount.Visible = True
    decDiscount = (decCost * 0.15)
    lblDiscount.Text = decDiscount.ToString("C")
    lblTotalPrice.Text = decFinalCost.ToString("C")

Else
    decFinalCost = decCost
    lblTotalPrice.Text = decFinalCost.ToString("C")
End If

Answer 1

Convert.ToInt32(txtAttending.Text) 不会就地转换文本，正如您的第一行代码似乎断言的那样；这是一个空操作。 txtAttending.Text 的类型为 System.String，并且将始终具有该类型。

您的案例陈述应该看起来更像这样:

If IsNumeric(txtAttending.Text) Then

    Dim decAttending = Convert.ToInt32(txtAttending.Text)

    Select Case decAttending
        Case Is = 1
            decCost = 695 * decAttending
        Case 2 To 4
            decCost = 545 * decAttending
        Case 5 To 8
            decCost = 480 * decAttending
        Case 9 To 16
            decCost = 395 * decAttending
    End Select
Else
    MsgBox("Please double check that your input is a number not greater than 16", , "Input Error")

此版本在进行数值运算时始终使用 System.Int32 变量 decAttending。