title: How to represent backspace in a string?
body: <p>Below is the code I am using to restrict user from entering any other characters except for the predefined ones. But using my code I cannot hit backspace. </p>
  
  <p>How to include backspace also ?</p>
  
  <pre><code> Dim s As String = "0123456789$"
  
   If s.IndexOf(e.KeyChar) = -1 Then
     e.Handled = True
   End If
  </code></pre>