title: Changing the standard behavior of a TextBox?
body: <p>I have an application that declares textboxes in various places, like in styles and datatemplates, and now I'm in a situation where I need to change every textbox's standard behavior for getting and losing focus. </p>
  
  <p>What's a good way to do this?</p>
  
  <p>I was thinking of two solutions: one is to derive a new class from TextBox, which I understand is generally frowned upon. The other is to create some kind of style that uses EventSetters, but since the styles and datatemplates in my application don't have codebehind files I donno how an event will find the appropriate event handler.</p>