title: Restrict a generic type
body: <p>I want to restrict the generic type parameter to:</p>
  
  <p>1) either that of a certain user defined reference type;</p>
  
  <p>OR</p>
  
  <p>2) any of the primitive types in the CLR;</p>
  
  <p>How do I say something to the effect of:</p>
  
  <pre><code>interface IDataManager&lt;T&gt;: IDataManager
      where T: IDataObject, T: ValueType
  </code></pre>