title: How do I detect if a Guid? is in a List<Guid?>
body: <p>With the following code:</p>
  
  <pre><code>Guid? x = null;
  List&lt;Guid?&gt; y = new List&lt;Guid?&gt;();
  y.Add(x);
  </code></pre>
  
  <p>I would expect the following code to return true <code>y.Contains(x);</code> but it returns false.</p>
  
  <p>So this is sort of a two part question.</p>
  
  <ol>
  <li>Why does it return false when clearly there x in the list?</li>
  <li>How would I loop through a Guid? List to check if a null <code>Guid?</code> or <code>Guid?</code> with value is in the list?</li>
  </ol>