title: Multiple Custom Controls with a set of shared base DependencyProperties
body: <p>Apologies if I'm grossly overlooking something here, but I'm a bit stumped:</p>
  
  <p>I'm developing a set of custom controls which all should share some common DependencyProperties. Say <code>DPropA</code> and <code>DPropB</code>. I want to avoid to copy/paste the same DPs over multiple controls, however, since they are custom controls, they all already inherit from their respective base control (Button, TextBox etc.) and MI is not possible. DP are static fields, so I can't put them in an Interface either.</p>
  
  <p>Also, I later may need to access some of these properties via reflection. This isn't an issue with properties that are near the top of the hierarchy (e.g. <code>Control.FontStyleProperty</code>), but since I can't declare a base class with my DPs this is also a problem.</p>
  
  <p>How can I solve this? I'm a bit suprised I barely found something about that problem, since I thought that sharing a common set of DPs for custom controls isn't actually an uncommon problem.</p>