title: How to create customized open file dialog in C#
body: <p>How can one create a user control that has the same functionality (along with some extended features) of OpenFileDialog in C#?  I've followed <a href="https://stackoverflow.com/questions/1769792/changing-button-text-in-openfiledialog-in-c-net">this</a>, but I could not find a solution for my problem. </p>
  
  <p>My requirement is to add an extra button in the dialog.  If that button gets clicked then the parent should be notified in the same manner as the <code>ok</code> and <code>cancel</code> buttons do.  </p>