Check if a character typed in a PasswordBox is numeric or not

Question

I have researched a little and it seems that there is not InputScope for passwordboxes in xaml. I'm setting up a pin field and only want numbers. if figure i will need to check the if the key pressed is numeric in C# before it writes it to the box. how would i go about doing this? it will also be checking if the length is 4 so it can automatically login which i already know how to do.

Answer 1

You can subscribe for KeyDown event on the PasswordBox. Maxmum Length can be restricted by setting MaxLength property.

private void OnKeyDown(object sender, KeyEventArgs e)
{
    if ((e.Key >= Key.D0 && e.Key <= Key.D9) || (e.Key >= Key.NumPad0 && e.Key <= Key.NumPad9))          
    return;

    e.Handled = true;            
}