title: Basic LINQ expression for an ItemCollection
body: <p>I have an <a href="http://msdn.microsoft.com/en-us/library/system.windows.controls.itemcollection.aspx" rel="noreferrer"><code>ItemCollection</code></a> that I'd like to query using LINQ. I tried the following (contrived) example:</p>
  
  <pre><code>var lItem =
      from item in lListBox.Items
      where String.Compare(item.ToString(), "abc") == true
      select item;
  </code></pre>
  
  <p>Visual Studio keeps telling me <code>Cannot find an implementation of the query pattern for source type 'System.Windows.Controls.ItemCollection'. 'Where' not found. Consider explicitly specifying the type of the range variable 'item'.</code></p>
  
  <p>How do I fix the problem?</p>