7

我发现这段代码让我的文本框只接受数字。

Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    Dim allowedChars As String = "0123456789"
    If allowedChars.IndexOf(e.KeyChar) = -1 Then
        ' Invalid Character
        e.Handled = True
    End If
End Sub

但是......用户不能使用退格按钮删除数字。那我该怎么办？

4

8 回答 8

10 
 Private Sub txtValue_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles                 txtValue.KeyPress
        'Dim allowedChars As String = "0123456789"
        'If allowedChars.IndexOf(e.KeyChar) = -1 Then
        '    ' Invalid Character
        '    e.Handled = True
        'End If
        'If (e.KeyChar = Microsoft.VisualBasic.Chr(8)) Then
        '    e.Handled = True
        'End If
        If Char.IsDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
            e.Handled = True
        End If
    End Sub
于 2011-06-02T11:55:28.703 回答
7

您还需要处理粘贴的文本（可能没有按键）。最好的方法是使用MaskedTextBox。

于 2011-01-26T04:37:03.030 回答
3

伏地魔

我开发了您的第一个代码以允许用户也删除。

这是代码：

Dim BACKSPACE As Boolean

Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
    If e.KeyCode = Keys.Back Then
        BACKSPACE = True
    Else
        BACKSPACE = False
    End If
End Sub

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If BACKSPACE = False Then
        Dim allowedChars As String = "0123456789"
        If allowedChars.IndexOf(e.KeyChar) = -1 Then
            e.Handled = True
        End If
    End If
End Sub

我希望我的代码对你有用:)

于 2015-04-06T14:07:25.997 回答
1

使用此代码，它将帮助您 

Public Function OnlyDigitsOnKeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)

Try

    If System.Char.IsDigit(e.KeyChar) = False And e.KeyChar <> Microsoft.VisualBasic.Chr(8)        And e.KeyChar <> Microsoft.VisualBasic.Chr(46) Or (InStr(sender.text, ".") > 0 And  e.KeyChar = Microsoft.VisualBasic.Chr(46)) 
    Then
                e.Handled = True
    End If
        Catch ex As Exception
            Common.ErrorHandler(ex)
        End Try
End Function
于 2011-01-26T04:42:12.483 回答
1

当我需要一个只接受数字的输入时，我通常使用这个NumericUpDown类。它也处理限制和小数。

于 2013-12-10T22:04:40.897 回答
0 
 Private Sub txtValue_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtValue.KeyPress
    Dim allowedChars As String = "."
    'If allowedChars.IndexOf(e.KeyChar) = -1 Then
    '    ' Invalid Character
    '    e.Handled = True
    'End If
    'If (e.KeyChar = Microsoft.VisualBasic.Chr(8)) Then
    '    e.Handled = True
    'End If
    If Char.IsDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False And allowedChars.IndexOf(e.KeyChar) = -1 Then
        e.Handled = True
    End If
End Sub
于 2013-06-10T16:05:47.430 回答
0 
Private Sub TMarksTextBox_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TMarksTextBox.KeyPress
        If e.KeyChar < "0" OrElse e.KeyChar > "9" AndAlso e.KeyChar <> ControlChars.Back Then
            e.Handled = True
        End If
End Sub
于 2013-11-03T16:57:16.553 回答
0

这是我写的一些代码。它允许用户删除，并且用户可以根据需要将文本框设为空白。它在用户键入不允许的字符时进行处理，并且在用户将文本粘贴到文本框中时也进行处理。如果用户将包含有效字符和无效字符的字符串粘贴到框中，则有效字符将出现在文本框中，而无效字符则不会出现。

它还具有确保游标正常运行的逻辑。（将文本设置为新值的一个问题是光标移回了开头。此代码跟踪原始位置，并进行调整以解决任何被删除的无效字符。）

这段代码可以放在任何文本框的 TextChaned 事件中。请务必从 TextBox1 更改名称以匹配您的文本框。

    Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged
    Dim selStart As Integer = TextBox1.SelectionStart
    Dim selMoveLeft As Integer = 0
    Dim newStr As String = "" 'Build a new string by copying each valid character from the existing string. The new string starts as blank and valid characters are added 1 at a time.

    For i As Integer = 0 To TextBox1.Text.Length - 1

        If "0123456789".IndexOf(TextBox1.Text(i)) <> -1 Then 'Characters that are in the allowed set will be added to the new string.
            newStr = newStr & TextBox1.Text(i)

        ElseIf i < selStart Then 'Characters that are not valid are removed - if these characters are before the cursor, we need to move the cursor left to account for their removal.
            selMoveLeft = selMoveLeft + 1

        End If
    Next

    TextBox1.Text = newStr 'Place the new text into the textbox.
    TextBox1.SelectionStart = selStart - selMoveLeft 'Move the cursor to the appropriate location.
End Sub

注意 - 如果您必须为一堆文本框执行此操作，您可以通过创建一个接受对文本框的引用作为参数的 sub 来制作通用版本。然后你只需要从 TextChanged 事件中调用 sub。

于 2013-12-10T21:56:40.387 回答