title: How to track which character is deleted in TextBox in WPF?
body: <p>I want to track which character is deleted by the user through Delete or BackSpace Key.</p>
  
  <p>I am handling TextBox_ChangedEvent of textbox.</p>
  
  <p>Can I extract the deleted character from <strong>TextChangedEventArgs</strong> <strong>e.Changes</strong> and if yes How can I do that?</p>
  
  <p>I want to restrict user to from deleting any characters from the TextBox. I want user can delete only two characters ( let's say "(" or ")" )</p>
  
  <p>Please suggest.</p>