title: How to select a distinct list of elements contained in another list?
body: <p>I have the following code</p>
  
  <pre><code>new Dictionary&lt;string,IEnumerable&lt;Control&gt;&gt;()
  {
      { "view1", new Control[] { contents, building, view1 }},
      { "view2", new Control[] { contents,  view2 }},
      { "view3", new Control[] { building,  view3 }
  }
  </code></pre>
  
  <p>How do I get a list of all the distinct controls using linq?</p>
  
  <p>The result should be:</p>
  
  <pre><code>{
      contents,
      building,
      view2,
      view3
  }
  </code></pre>