序列化类时出现NetDispatcherFaultException

Question

I have this classes:

public class Container
{
  public IEventQueue GetEventQueue(){returns a DerivedEventQueue}
}

ComVisible(true), ComDefaultInterface(typeof(IEventQueue ))]
   [ClassInterface(ClassInterfaceType.None)]
   [Guid("XXX-XXX-XXX-XXX")]
   [ProgId("XXXX")]
   [DataContract]
   [KnownType(typeof(DerivedEventQueue))]
   public EventQueue: IEventQueue
   {
      public MyEvent GetEvent(){...}
   }


 [DataContract]
 [KnownType(typeof(DerivedEventQueue))] //doesnt matter if I have this line or not, I got the same error
//[System.Serializable]
  public class DerivedEventQueue: EventQueue, IEventSink
  {
   ...
  }

When I called GetEventQueue I got the following exception:

System.ServiceModel.Dispatcher.NetDispatcherFaultException: The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter XXXX:GetEventQueueResult. The InnerException message was 'Element 'XXXX:GetEventQueueResult' contains data of the 'XXX:DerivedEventQueue' data contract. The deserializer has no knowledge of any type that maps to this contract. Add the type corresponding to 'DerivedEventQueue' to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding it to the list of known types passed to DataContractSerializer.'. Please see InnerException for more details. ---> System.Runtime.Serialization.SerializationException: Element 'XXXX:GetEventQueueResult' contains data of the 'XXXX:DerivedEventQueue' data contract. The deserializer has no knowledge of any type that maps to this contract. Add the type corresponding to 'DerivedEventQueue' to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding it to the list of known types passed to DataContractSerializer.

DerivedEventQueue is in the KnownType property in the base class, so I don't know why I am getting this exception. Can anyone tell me why I am getting this exception? Thanks!

Answer 1

I'd yry to add known type aytribite on the service level.

Also, i think the error is comes from interface you are returning, since wcf does not know how to deserialize it.

For.more details about known types, See also http://msdn.microsoft.com/en-us/library/ms730167.aspx