ASP.NET MVC 4 Web API：如何异步处理需要从异步WCF服务回调中提取结果的请求

Question

Suppose I implemented a webservice using ASP.NET MVC 4 that has a controller that exposes one method:

Response Process(Request request);

This webservice communicates with a middle-tier service for processing requests. The middle-tier service contract service looks something like this:

[ServiceContract(CallbackContract=typeof(IServiceCallback))]
interface IService
{
    [OperationContract(IsOneWay=true)]
    void Process(Request request);
}

interface IServiceCallback
{
    [OperationContract(IsOneWay=true)]
    void Processed( Response response );
}

This service asynchronously processes a request via the matching Process/Processed methods.

What's the best way to asynchronously make a call to from the web service to this middle-tier service? I'm having trouble seeing how to get the response from the callback thread to return to the calling client, when the callback method obviously returns in a different worker thread?

Thanks for any help given.

Answer 1

You have to use async and await. Read this link http://msdn.microsoft.com/en-us/library/vstudio/hh300224.aspx

Answer 2

Try this in your calling code.

public void DoStuff()
{

    using(var proxy = new Proxy())
    {
        var result = await proxy.Process();
        Task.Run(() => Processed(result));
    }
}

Or this...which works with .net 4

public void DoStuff()
{

    using(var proxy = new Proxy())
    {
        proxy.Process().ContinueWith(result => Processed(result), TaskCreationOptions.None);
    }
}