title: I can't access datacontext
body: <p>I'm using VS 2010 Ultimate .NET 4.0 in ASP.NET project, I have a DataClassesDataContext in the 
  App_Code folder and a customer class in the same folder, which tries to instantiate DataClassesDataContext</p>
  
  <pre><code>DataClassesDataContext db = new DataClassesDataContext();
  </code></pre>
  
  <p>But I'm getting "the type or namespace DataClassesDataContext" could not be found, are you
  missing a using directive or an assembly reference? </p>