title: Operation not supported in the WCF Test Client
body: <p>I created a WCF service and to the default service I added another operation contract on the main DataContract:</p>
  
  <pre><code>[OperationContract]
  void DoSomething(UserData data);
  </code></pre>
  
  <p>Then I have something like this (simplified for the purpose of example) below. The problem is that even though ALL classes in the hierarchy are decorated with DataContract and ALL their members decorated with DataMember, when I use the WCF Test Client it has a red icon indicating that "the operation is not supported in the WCF test client".</p>
  
  <pre><code>[DataContract]
  public class UserData {
     [DataMember]
     public uint One { get; set; }
  
     [DataMember]
     public CompositeType Extra { get; set; }
  
     public UserData() { ctor. code }
  }
  
  
  [DataContract]
  public class CompositeType {
      [DataMember]
      public uint Two { get; set; }
  
      public UserData() { ctor code }
  }
  </code></pre>