Question

我有两个接受输入的文本框。数据计算并显示在ListBox。

中

我根本没有显示消息框。因此，无论我输入什么数据，我都会发布所有内容，现在它们都在显示。有趣的是计算是正确的并且显示正确。

如果两个文本框中的数据不是数字，为空或小于零，我需要显示消息框。

如果有人能给我一个想法，我将不胜感激。

' Did user enter a numeric value?
If IsNumeric(txtHourlyWage.Text) Then
    decHourlyWage = Convert.ToDecimal(txtHourlyWage.Text)
End If

' Is Hourly Wage greather than zero?
If decHourlyWage > 0 Then
End If

' Did user enter a numeric value?
If IsNumeric(txtExpectedRaise.Text) Then
    decExpectedRaise = Convert.ToDecimal(txtExpectedRaise.Text)
End If

' Did user enter a numeric value?
If decExpectedRaise > 0 Then
End If

' If txtHourlyWage.Text = "" Or txtExpectedRaise.Text = "" Then
'MsgBox("Input Cannot Be Empty")

iNextyear = (decHourlyWage * decHoursInWeek) * (decWeeksInYear)

iNextyear = iNextyear
decAnnualPay = iNextyear
lstAnnualPay.Items.Add(decAnnualPay.ToString("c"))

For intNumber = 1 To 9
  '   Body of Loop
  iNextyear = iNextyear + iNextyear * CDec((txtExpectedRaise.Text)) / 100
  decAnnualPay = iNextyear
  lstAnnualPay.Items.Add(decAnnualPay.ToString("c"))
Next

' Display error message if user entered a negative number
MsgBox("You Entered " & txtHourlyWage.ToString() & ". Please Enter a Positive Number ", , "question")

MsgBox("You Entered " & txtExpectedRaise.ToString() & ". Please Enter a Positive Number ", , "question")


'Display error message if user entered a nonnumeric value
MsgBox("Please Enter A Number ", , "question")
txtHourlyWage.Text = ""
txtHourlyWage.Focus()

MsgBox("Please Enter A Number ", , "question")
txtExpectedRaise.Text = ""
txtExpectedRaise.Focus()
btnCompute.Visible = False

Answer 1

以这种方式使用更强大的decimal.TryParse

'  Did user enter a numeric value?
If Not decimal.TryParse(txtHourlyWage.Text, decHourlyWage) OrElse _
                        decHourlyWage < 0 Then
   MsgBox("You Entered an invalid value for the Hourly Wage (negative, zero or empty", "Number")
   return
 End If

相同的模式适用于其他值。

消息框未按预期工作

1 个答案: