vb.net 中只允许一个数字

Question

Im new in programming and i want to ask for a help. I'm asking for the code in vb.net where after i put period or "." In the textbox I want the textbox to accept only number 5. The textbox will not accept any letters or numbers or special characters in my textbox after I put period or "."

Answer 1

This might help you:

Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
    If Trim(CType(sender, TextBox).Text).EndsWith(".") AndAlso (e.KeyData <> Keys.D5) Then
        e.SuppressKeyPress = True
        e.Handled = True  
        Console.WriteLine("Type another key. this is not number 5")
    End If
End Sub