title: List.except on custom class
body: <p>lets say I have a custom class:</p>
  
  <pre><code>public class WineCellar
  {
  
      public string year;
      public string wine;
      public double nrbottles;
  }
  </code></pre>
  
  <p>Lets say I now have a List of this custom class:</p>
  
  <pre><code>List&lt;WineCellar&gt; orignialwinecellar = List&lt;WineCellar&gt;();
  </code></pre>
  
  <p>containing these items:</p>
  
  <pre><code>2012 Chianti 12
  
  2011 Chianti 6
  
  2012 Chardonay 12
  
  2011 Chardonay 6
  </code></pre>
  
  <p>I know that if I want to compare two list and return a new list that has only items that are not in the other list I would do:</p>
  
  <pre><code>var newlist = list1.Except(list2);
  </code></pre>
  
  <p>How can I extend this to a custom class? Lets say I have:</p>
  
  <pre><code>string[] exceptionwinelist = {"Chardonay", "Riesling"};
  </code></pre>
  
  <p>I would like this to be returned:</p>
  
  <pre><code>List&lt;WineCellar&gt; result = originalwinecellar.wine.Except(exceptionwinelist);
  </code></pre>
  
  <p>This pseudocode obviously doesnt work but hopefully illustrates what I m trying to do. This shoudl then return a List of the custom class winecellar with following items:</p>
  
  <p>2012 Chianti 12</p>
  
  <p>2011 Chianti 6</p>
  
  <p>Thanks.</p>