title: VBA OOP extending existing classes
body: <p>I'm a rookie at VBA(Excel) but I know some OOP stuff from java.  What I want to do is extend the class MSForms.TextBox to add my own constructors and properties.  I've tried using the implements keyword but my class won't compile.  It would also be helpful to add these fields into some kind of container variable since they're arranged in a 9x9 pattern.  Here's what I want my custom textbox to do.  (It's for a game)</p>
  
  <p>I need to be initiate it and place it on the form and put initial text into the box based on what is passed to the constructor.  I also would like to have it check the values at runtime with an event to make sure they comply with the game rules.  If it does not comply I would like to change the background color to red.  </p>
  
  <p>I'm able to do all of this when I just make a bunch of form controls the old fashioned way and use a sub controlled by a button to check the text box values.</p>
  
  <p>Any help on extending classes would be much appreciated.
  Thanks</p>