title: Help Linqifying collection to Dictionary
body: <p>I'm refactoring this code and was trying to think of a simple linq expression to populate this Dictionary. </p>
  
  <pre><code>IEnumerable&lt;IHeaderRecord&gt; headers = PopulateHeaders();
  var headerLocationLookup = new Dictionary&lt;string, IHeaderRecord&gt;();
  
  foreach (var header in headers)
  {
  //destination locations can repeat, if they do, dictionary should only contain the first header associated with a particular location
      if (!headerLocationLookup.ContainsKey(header.DestinationLocation)) 
      {
           headerLocationLookup[header.DestinationLocation] = header;
      }
  }
  </code></pre>
  
  <p>I could only come up with implementing a custom IEqualityComparer and using that in an expression such as this...</p>
  
  <pre><code>headers.Distinct(new CustomComparer()).ToDictionary();
  </code></pre>
  
  <p>Is there a way to do it all inline without the custom IEqualityComparer?  Thanks in advance.</p>