title: Exception in System.Data.Entity.dll but was not handled in user code
body: <p>I need to count the number of the rows in my database with the entity framework. I am using the LINQ method &quot;Count&quot;.</p>
  <p>Here is the code:</p>
  <pre><code>QvDb dba = new QvDb();
  if (dba.KUser.Count(us =&gt; us.FacebookId == values[&quot;FacebookId&quot;]) == 0)
  </code></pre>
  <p>As you can see the <code>values[&quot;FacebookId&quot;]</code> it's a post array variable, and the <code>dba</code> object variable it's the database model builder.</p>
  <p>When I am trying to access to the page i got this exception:</p>
  <blockquote>
  <p>An exception of type 'System.NotSupportedException' occurred in
  System.Data.Entity.dll but was not handled in user code</p>
  <p>Additional information: LINQ to Entities does not recognize the method
  'System.String get_Item(System.String)' method, and this method cannot
  be translated into a store expression.</p>
  </blockquote>
  <p>For the record, the array is not null. It is a string that posted from the form.</p>