Question

该代码只是要求6个不同学院的通过率。费率必须介于1到100之间。

我希望它只允许数字。我尝试过使用IsNumeric，但我一定不能正确使用它。这是我到目前为止所做的：

For i As Integer = 0 To 5
    passRate(i) = InputBox("Enter the pass rate for " & colleges(i) & " college")
    While passRate(i) > 100 Or passRate(i) < 0
        MsgBox("Error must be a number and be between 0 and 100")
        passRate(i) = InputBox("Enter the pass rate for " & colleges(i) & " college")
    End While
Next i

Answer 1

将此功能用于检查值

Private Function IsInputNumeric(input As String) As Boolean
        If String.IsNullOrWhiteSpace(input) Then Return False
        If IsNumeric(input) Then Return True
        Dim parts() As String = input.Split("/"c)
        If parts.Length <> 2 Then Return False
        Return IsNumeric(parts(0)) AndAlso IsNumeric(parts(1))
End Function

并像这样使用

For i As Integer = 0 To 5

    passRate(i) = InputBox("Enter the pass rate for " & colleges(i) & " college")
    If IsInputNumeric(passRate(i)) Then
        'handle numeric input
    Else
        'handle not a number
    End If
    While passRate(i) > 100 Or passRate(i) < 0
        MsgBox("Error must be a number and be between 0 and 100")
        passRate(i) = InputBox("Enter the pass rate for " & colleges(i) & " college")

    End While

Answer 2

我看到了一些需要注意的事项。

IsNumeric不测试整数。它会返回true 为＆＃34; 1.5＆＃34;因为它是数字的。我假设你在看输入结果的整数值为1到100。
输入框返回一个字符串。如果要将其与整数类型进行比较，则必须进行某种形式的解析（隐式或显式）。

为了避免这种转换，您可以使用简单的RegEx。这个将验证它是1到100之间的整数：

Function IsValid(Byval inputString as String) as Boolean
    Dim validValues As New Regex("^[1-9]?[0-9]{1}$|^100$")
    Return validValues.IsMatch(inputString )
End Function

遗憾的是，RegEx可能有点多......所以这是检查输入字符串是否会转换为整数的另一种方法，如果是这样，它的值是1到100之间。

Function IsValid(Byval inputString as String) as Boolean
  Dim result As Boolean = False
  Dim inputAsInteger as Integer = 0
  If Integer.TryParse(value, inputAsInteger) Then
     result = inputAsInteger > 0 And inputAsInteger <= 100)
  End If
  Return result
End Function

你可以这样打电话：

   Dim validInput as Boolean = False
   While Not validInput
      validInput = IsValid(InputBox("Enter the pass rate for " & colleges(i) & " college")
   Loop

Answer 3

 Private Sub txbDwellTime_KeyPress(sender As Object, e As KeyPressEventArgs) Handles txbDwellTime.KeyPress
    pNumDecOnly(e)
    'txbDwellTime.Text = ""
End Sub

Public Sub pNumDecOnly(ByVal e As System.Windows.Forms.KeyPressEventArgs)
    If (Asc(e.KeyChar) >= 48 And Asc(e.KeyChar) <= 57 Or Asc(e.KeyChar) = 46) Then
        'good job do nothing we only allow positive Decimal numbers in this field
        'Asc(e.KeyChar) 48 Through 57 i.e. 0 through 9 Or Asc(e.KeyChar) 46 (dot= .)
    Else
        e.Handled = True
        MsgBox("Only Positive Decimal Numbers Allowed this field")
    End If
End Sub

这将只允许使用ASCII表的正十进制数，您应该可以对其进行修改以供自己使用

如何让InputBox只接受数字

3 个答案: