title: Can MEF be used to get the System.Type of classes marked [Export]?
body: <p>I've been successfully using MEF to obtain exported class instances. However, I came across a situation where I need to enumerate a set of exported derived classes without instantiating them. I've looked up <code>CompositionContainer</code>'s documentation and it only seems to be able to return object instances.</p>
  
  <p>I know I could have a static Type field in each derived class and export it, or do my own reflection, but I'd like to know if there's a build-in way to mark classes with the <code>[Export]</code> attribute and then enumerate their <code>System.Type</code>.</p>