title: Masking a textbox for Numbers only but wont accept BackSpace
body: <p>I have a textbox that I would like for only numbers. But if I hit the wrong number, I cant backspace to correct it. How can I allow backspaces to work. Thanks</p>
  
  <pre><code>    private void amount_PaidTextBox_KeyPress(object sender, KeyPressEventArgs e)
      {
          if (Char.IsNumber(e.KeyChar) != true)
          {
              e.Handled = true;
          }
      }
  </code></pre>