title: VS2010 target .net 2.0 and System.Runtime.Serialization
body: <p>Why can't I add a reference to System.Runtime.Serialization when targeting .net 2.0?</p>
  
  <p>Also if I convert a vs2005 project using System.Runtime.Serialization the vs2010 conversion fails with a build error.</p>
  
  <p>I'm using the DataContract class and the compiler says</p>
  
  <p>The type or namespace name 'DataContract' could not be found (are you missing a using directive or an assembly reference?) C:\Users\my\ClassLibrary1\Class1.cs 8 6 ClassLibrary1</p>