title: Adding an interface to a partial class
body: <p>I have a class that is generated by a third party tool:</p>
  
  <pre><code>public partial class CloudDataContext : DbContext 
  {
      // ...SNIPPED... 
      public DbSet&lt;User&gt; Users { get; set; } 
  
  }
  </code></pre>
  
  <p>I create a partial class and then assign an interface so that I can inject this class later:</p>
  
  <pre><code>public partial class CloudDataContext : IDataContext
  {
  
  }   
  </code></pre>
  
  <p>The <code>IDataContext</code> has the single property <code>Users</code>.</p>
  
  <p>This won't compile, the compiler complains that the interface isn't implemented.</p>
  
  <p>If I move the interface to the generated class, it works fine. I can't do that though as it's generated code.  </p>
  
  <p>How can I apply an interface to a partial class to expose the class as defined above?                                                                                                                                                                                 </p>