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WP7 + Waiting for operation to complete before continuing

I have a Windows Phone 7 application using Silverlight with C #. This application has a method that runs multiple web service requests. At another point in my code, I have code that looks like this:

myProgressBar.Visibility = Visibility.Visible;
while (AreWebServiceCallsDone() == false)
{
  // Need "waiting" code here
}

// Proceed

How do I make my UI “wait” a short amount of time without blocking the user interface, and then check again if my web service calls are being made?

Thank!

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2 answers

The answer is not to make the user interface wait at all, but to "go with the (asynchronous) stream."

, # 5 , CLR, Silverlight WP7.

Microsoft.Phone.Reactive, WP7 Reactive Extensions (Rx) SDK. , , , .

, - , :

  • - IObservable 1
  • Do, "" (, )
  • Select "" , ( )
  • ForkJoin , .

1 IObservable , . , WebClient, , Observable DownloadStringAsync ( , ):

public static class ObservableWebClient
{
    public static IObservable<string> DownloadStringObservable(
        this WebClient webClient, Uri uri)
    {
        return Observable.Create(observer =>
        {
            var disposable = new CompositeDisposable();

            var completedObservable = Observable.FromEvent<
                    DownloadStringCompletedEventHandler, 
                    DownloadStringCompletedEventArgs
                >(
                    h => new DownloadStringCompletedEventHandler(h),
                    h => webClient.DownloadStringCompleted += h,
                    h => webClient.DownloadStringCompleted h= h
                );

            disposable.Add(completedObservable
                .SelectMany(ev =>
                {
                    return (ev.EventArgs.Error != null)
                        ? Observable.Throw<string>(ev.EventArgs.Error)
                        : Observable.Return(ev.EventArgs.Result);
                })
                .Subscribe(observer));

            disposable.Add(Disposable.Create(
                () => webClient.CancelAsync()));

            return disposable;
        });
    }
}

:

, Do + "normalizing", (String). , ( ForkJoin, )

var webClientA = new WebClient();
var webClientB = new WebClient();
var webClientC = new WebClient();

Observable.ForkJoin(
        webClientA.DownloadStringObservable(uriA),
        webClientB.DownloadStringObservable(uriB),
        webClientC.DownloadStringObservable(uriC),
    )
    .ObserveOnDispatcher()
    .Subscribe(dataArray =>
    {
        // All three have completed
        this.DataA = dataArray[0];
        this.DataB = dataArray[1];
        this.DataC = dataArray[2];
    });
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