title: XDocument.Descendants("somethinghere").Count() method does not exist
body: <p>I am trying to do a simple count of some descendants using <a href="http://en.wikipedia.org/wiki/Language_Integrated_Query#LINQ_to_XML" rel="nofollow">LINQ to XML</a> and the "Count()" method does not exist for me? </p>
  
  <p>Example:</p>
  
  <pre><code>using System.Xml.Linq;
  
  XDocument doc = XDocument.Load( "somexmlfile" );
  int count = doc.Descendants("somethinghere").Count();
  </code></pre>
  
  <p>The above won't compile, because it doesn't recognize the <code>Count()</code> method. </p>