title: Getting a compile error in c# about not referencing System.XML, yes System.XML is being reference
body: <p>I am trying to add a new feature to an old program I wrote. However, when trying to get the program to build in VS express it spits back an error message to me.</p>
  
  <blockquote>
    <p>Error 1   The type 'System.Xml.Serialization.IXmlSerializable' is
    defined in an assembly that is not referenced. You must add a
    reference to assembly 'System.Xml, Version=4.0.0.0, Culture=neutral,
    PublicKeyToken=b77a5c561934e089'. C:\Path\To\File\summaryForm.cs  101 18
    SerialController</p>
  </blockquote>
  
  <p>However the thing is at the top of the cs file, it has</p>
  
  <pre><code>using System;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Windows.Forms; 
  using System.Xml;
  </code></pre>
  
  <p>Any ideas whyits not recognizing the XML reference?</p>