如何只允许将'0'和'1'放入文本框中

Question

我发现很多方法可以限制用户输入字母字符，但我希望更具体。我正在制作一个二进制计算器，我希望用户只能填写数字'0'和'1'。

Answer 1

虽然有很多方法可以做到这一点，但我喜欢这种方法：

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    Dim valid_values As String = "01"
    If Not valid_values.Contains(e.KeyChar) Then
        e.Handled = True
    End If
End Sub

Answer 2

这将确保按下的键为0或1.否则它将表现为没有按下任何键。

Private Sub txtBox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtBox.KeyDown

If Not (e.KeyCode = Keys.0 OR e.KeyCode = Keys.1) Then
   e.Handled = True
EndIf 

End Sub

Answer 3

应用于textbox_keypress事件..

Private Sub txtbox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtbox.KeyPress 
  Dim k As Byte = Asc(e.KeyChar)    

  If Not (e.KeyChar = "0" Or e.KeyChar = "1" Or k = 8 Or k = 13) Then e.Handled = True

End Sub