title: test if property in entity can be ordered using orderBy
body: <p>i am using a linq dynamic to do a dynamic orderBy. How do I get only the property names of an entity that is must have a type that is order comparable. The entity has base types (string, ints) and complex objects which I don't the user to filter by.</p>
  
  <pre><code>var OrderByOptions = typeof (Project).GetProperties().Select(x =&gt; x.Name).ToList(); //I only want order comparable property names here
  
  var userSelectable = 2;
  
  var pjs = _pjRepo.Projects.Where(x =&gt; x.Active == true).OrderBy(OrderByOptions[userSelectable]).ToList();
  </code></pre>