vb.net 在 Visual Basic.NET 中禁用字母和特殊字符
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Disabling alphabetic letters and special characters in Visual Basic.NET
提问by Zukrooo
Im new to visual basic and im unsure on how to disable alphabetic and special characters.
我是visual basic的新手，我不确定如何禁用字母和特殊字符。
I Only want the user to be able to input numbers.
我只希望用户能够输入数字。
Im using this code im know there is an easier way to do it and all help is appreciated
我正在使用此代码，我知道有一种更简单的方法可以做到，并且感谢所有帮助
I get the message box when I input alphabetic characters and when I input numbers. i dont want to get the message box when i input numbers.
当我输入字母字符和输入数字时，我会收到消息框。我不想在输入数字时收到消息框。
Private Sub txtCustom_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtCustom.KeyDown
If (e.KeyCode = Keys.Enter) Then
e.SuppressKeyPress = True
If (e.KeyCode = Keys.A Or Keys.B Or Keys.C Or Keys.D Or Keys.E Or Keys.F Or Keys.G Or Keys.H Or Keys.I Or Keys.J Or Keys.K Or Keys.L Or Keys.M Or Keys.N Or Keys.O Or Keys.P Or Keys.Q Or Keys.R Or Keys.S Or Keys.T Or Keys.U Or Keys.V Or Keys.W Or Keys.X Or Keys.Y Or Keys.Z) Then
Beep()
MsgBox("Please Input A Numerical Value")
txtCustom.Text = ""
Else
RandNumAllow = txtCustom.Text
End If
End If
End Sub
回答by LarsTech
Try using the KeyPress event instead:
尝试改用 KeyPress 事件：
Private Sub TextBox1_KeyPress(sender As Object, _
e As KeyPressEventArgs) Handles TextBox1.KeyPress
e.Handled = Not Char.IsNumber(e.KeyChar)
End Sub
But this won't stop someone from using the clipboard. It's probably better to use the MaskedTextBox control instead.
但这不会阻止某人使用剪贴板。最好改用 MaskedTextBox 控件。
回答by The Only Smart Boy
Sorry for the late response this code will solve all the issues, copying from clipboard and shift + number for special characters as it uses the TextChanged event try it out.
抱歉，此代码将解决所有问题，因为它使用 TextChanged 事件，所以从剪贴板复制和特殊字符的 shift + number 复制，此代码将解决所有问题。
Dim charactersAllowed As String = "1234567890"
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim theText As String = TextBox1.Text
Dim Letter As String
Dim SelectionIndex As Integer = TextBox1.SelectionStart
Dim Change As Integer
For x As Integer = 0 To TextBox1.Text.Length - 1
Letter = TextBox1.Text.Substring(x, 1)
If charactersAllowed.Contains(Letter) = False Then
SystemSounds.Beep.Play()
theText = theText.Replace(Letter, String.Empty)
Change = 1
End If
Next
TextBox1.Text = theText
TextBox1.Select(SelectionIndex - Change, 0)
End Sub
You can replace the value of charractersAllowed with whatever characters you want to allow
您可以将 charactersAllowed 的值替换为您想要允许的任何字符
回答by chervani
The code you were looking for I think looks like this.
您正在寻找的代码我认为看起来像这样。
For the keypress event on whatever text or input box your trying to control input into
对于您试图控制输入的任何文本或输入框上的按键事件
If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso 'restricts anything but number keys
e.KeyChar <> ControlChars.Back Then 'allows use of backspace
e.Handled = True
End If
