Question

Coming from a Java background, this is the way I’m thinking:

The server provides an object to the client. This object should be able to execute on the server.

Server:

private string _S = "A";

public interface IFoo { void Bar(); }

private class Foo : IFoo {
    void Bar() { _S = "B";}
}

public IFoo GetFoo() { return new Foo(); }

Client:

IFoo foo = serverChannel.GetFoo();
foo.Bar();

Is this possible? Or is my understanding wrong and this is not how it works in WCF? What would be a better design?

Answer 1

No, I don’t think that’ll work. You see: WCF is not some kind of a remoting, remote-object, or remote-procedure call mechamism.

WCF at its core is a messaging infrastructure. Your client make a call to a method on a client-side proxy; the WCF runtime on the client captures the input parameters and the method name and a few more bits and pieces, serializes them into a message (either text or binary), and send that message across the wire (using whatever transport you like). The server does the same thing in reverse, deserializes the message, instantiantes a service class, executes a method on that class, and packages the return values back into a serialized message.

But there’s really no connection or remoting link between client. Anything that goes between the two has to be serializable – into XML text at its core. You can pass around concrete classes and so on – but you cannot pass around interface, object references etc.