CODEWITHSUNDEEP
wcfsystem.reactive
Steve Chadbourne
Steve Chadbourne

Reputation: 6953

How do I simply call an asyc WCF service method using Rx

I have been struggling to figure out how to use Rx. Most of the examples are out of date, reference Begin/End or are long and complex.

I have a simple WCF service method that takes an int and returns a JobMaster object.

Here is how I call it at the moment:

    public static void GetJob(int jobId)
    {
        KernServiceClient.GetJobCompleted += GetJobCompleted;
        KernServiceClient.GetJobAsync(jobId);
    }

    private static void GetJobCompleted(object sender, GetJobCompletedEventArgs e)
    {
        // JobMaster available in e.Result
    }

How do I change this to use Rx?

EDIT

Thanks to Paul's help I have got most of the way there. This is what it looks like now. Only problem is the Subscribe never fires. Any ideas?

    public static JobMaster GetJob(int jobId)
    {
        JobMaster retval = null;

        IKernService kernServiceInterface = KernServiceClient;

        var getJobFunc = Observable.FromAsyncPattern<int, Server.KernMobileWcfService.JobMaster>(
            kernServiceInterface.BeginGetJob, kernServiceInterface.EndGetJob);

        var result = getJobFunc(jobId);

        result
            .Subscribe
            (
                onNext: x => retval = ConvertJobMaster(x),
                onError: ex => ShowError(ex.Message)
            );

        return retval;
    }

Upvotes: 0

Views: 649

Answers (3)

paul3654
paul3654

Reputation: 1

what are you doing with retval when you return it? if you need to do more processing when on next completes do it in the onCompleted event of the subscription

Upvotes: 0

Bart De Smet
Bart De Smet

Reputation: 1

Seems you're returning "retval" even though you're computing it asynchronously and assigning it from your OnNext handler. Your logic upon receiving the value from the service should be moved into the OnNext handler, or you should return the IObservable to the caller.

Upvotes: 0

Ana Betts
Ana Betts

Reputation: 74652

http://blog.paulbetts.org/index.php/2010/09/26/calling-web-services-in-silverlight-using-reactivexaml/ // Ignore the ReactiveXaml part

Summary: Cast KernServiceClient to the Interface it implements to get back the Begin/End methods, use FromAsyncPattern.

Upvotes: 1

Related Questions