Question

I am trying to use Generic DataContract class so that I don’t have to implement several types for a collection of different objects.

Exp :

I have a Profile object which contains a collection of objects.

So I want to have one Profile<Foo> and Profile<Foo1> where profile contains a collection of Foo or Foo1 objects.

I have been reading that WCF does not support generic classes and actually the error that I get is the following.

Type 'GL.RequestResponse.ProfileResponse1[T]’ cannot be exported as a schema type because it is an open generic type. You can only export a generic type if all its generic parameter types are actual types.`

Now the ProfileResponse is this Profile object that I am trying to use.

Now in my host I am doing the following. :

 ServiceConfig(typeof(ProfileHandler<EducationResponse>).Assembly, 
               typeof(ProfileRequest).Assembly,
               typeof(Container)).Initialize();

This is dhe definition of the handler with the datacontract.

   public class ProfileHandler<T> : RequestHandler<ProfileRequest,
                                                   ProfileResponse<T>> 

The Container is using Windsor Container to register the objects.

The registration works fine but after I instantiated the Service Host for WCF processor, and call Open Method of the host I get the above error.

Is there really no way for me to write generic response requests for wcf with agatha ?
It feels like such a waste to have to define a Profile container class for each type being contained in that collection.

thanks.

Answer 1

One cannot have open generic handlers, because the server side needs to know what the type is.
One can use so called closed generic methods. This way the server side knows the types for witch to load the handler.

Also, one could potentially configure Agatha so that it allows to receive extra information related to the request. In this case, it would be the type wrapped in the response.

One could do this by defining a a BaseRequest class and having all the request extend this class. This class can have a property which takes the type of the response. Or the type to be wrapped in the response.

In the process, when examining the request, the process can get the type to be wrapped in the Response, so that i knows how to load the class.

I have not implemented this, since it would take too much time and I am not sure I want to be responsible for maintaining Agatha for our application, but this is how I would do it.