带有异步服务的 WCF SharedInterface 定义

Question

I have a problem with an Interface which defines my Services. I use the same interface in Silverlight and WPF and my Backend.

For Example:

#if !SILVERLIGHT
    [OperationContract(IsOneWay = false)]
    SecurityOperationInfo LogonUser(string sessionId, string username, string password);
#else
    [OperationContract(IsOneWay = false, AsyncPattern = true)]
    IAsyncResult BeginLogonUser(string sessionId, string username, string password, AsyncCallback callback, object state);        
    SecurityOperationInfo EndLogonUser(IAsyncResult result);
#endif

The problem is, I use the Interface in Silverlight (it is working good). Now I also want to use the Async way in WPF, but I don't want to need to implement Begin and End on the Server side! But my WPF Project is linking to the same DLL which implements this Interface!

Is there any way to achieve this in a easy way?

Answer 1

Luckily, in WCF you can have separate interfaces for client- and server-side implementations. Your server-side implementation can be completely async while the client-side interface has a synchronous operation, and vice versa. In your case I would create a derived interface for client-side async operations. That way you serverside implementation can remain synchronous, while the client can implement the operations asynchronously.

[ServiceContract(Name = "IMyService", ...)]
public interface IMyService {
   [OperationContract(IsOneWay=false)]
   SecurityOperationInfo LogonUser(string sessionId, string username, string password);

   // other methods ...
}

[ServiceContract(Name = "IMyService", ...)]
public interface IMyServiceAsync : IMyService {
    [OperationContract(IsOneWay = false, AsyncPattern = true)]
    IAsyncResult BeginLogonUser(string sessionId, string username, string password, AsyncCallback callback, object state);        
    SecurityOperationInfo EndLogonUser(IAsyncResult result);
}

Note that the name of the both service contracts must match, otherwise WCF won't be able to connect to the service.