Question

I have the following scenario.

My environment is Visual Studio 2010, Framework 4.0.

There is a dll I don’t control with certain (fairly complex) object in it. I need to call that object in my wcf service then pass it to the client application, so client application would continue working with it.

I create data contract in the wcf, something like this:

  [DataContract]
    public class Test
    {       
        [DataMember]
        public dllCustomObjectType MyTest;
    }

Then I create an interface for this data contract:

 interface ITest
    {    
        [OperationContract]
        dllCustomObjectType GetMyTest(int Id);
    }

Then I implement the interface and use the implemented method in the client application.

Client application has references to the same dll I don’t control.

When I try to run it (in fact, even when I update service reference) I am getting the error that request failed and metadata contains a reference that cannot be resolved.

I can replicate that object in my data contracts (and it is a lot of work) but I am wondering if there is a way to pass the value of that object type to the client application without recreating the object.

I would appreciate any assistance.

Thanks!

Answer 1

For this to work, WCF needs to know how to convert “dllCustomObjectType” to/from XML. That is, the “dllCustomObjectType” type needs to be a type that’s designed with serialization in mind, recognized by the DataContractSerializer (see http://msdn.microsoft.com/en-us/library/ms731923.aspx ). If the creators of your 3rd-party DLL never designed that type to support serialization, you will basically need to write your own serialization/deserialization code for it. You can do it by converting the type into your own custom type (simplest) or by creating a Data Contract Surrogate ( http://msdn.microsoft.com/en-us/library/ms733064.aspx ). Another option is to have a custom type (e.g. “Test” in your example above) implement some dynamic serialization interface (e.g. IXmlSerializable or ISerializable) where you would manually serialize the contained “dllCustomObjectType”, and then use Test instead of dllCustomObjectType in your service contract.