CODEWITHSUNDEEP
c#multithreadingnetwork-programmingwindows-runtimewindows-phone-8.1
WPMed
WPMed

Reputation: 1414

Background thread in Windows Phone 8.1 app

I'm working on a Windows Phone 8.1 shopping application. I have a continously running thread in the app which downloads the users basket and saves it in a local cache to imporve performance. So far what I have is something like this:

while(UserLoggedIn)
{
    await Networking.getBasket();
    await Task.Delay(5000);
}

This thread is started when app resumes. My question is: What is the best approach to controll such a thread? On the app resuming it seems really slow, and sometimes it blocks the UI thread, although it's fully async. How can I improve performance?

EDIT

According to Romasz's suggestion, I used a Timer like this:

Declaring it:

Timer _getBasketTimer;

Initializing it in the App's constructor:

_getBasketTimer = new Timer(getBasketCallback, null, 5000, Timeout.Infinite);

Defining its callback:

private async void getBasketCallback(Object state)
{
    if (JSONCache.getSessionID() != "" && Networking.LoginInProgress == false)
        await Networking.getBasket();

    //The Change method may be called when the Timer object is already Disposed (I debugged it, and the exception did occur sometimes)
    try
    {
        _getBasketTimer.Change(5000, Timeout.Infinite);
    }
    catch(ObjectDisposedException)
    {

    }
}

Disposing it in the App's Suspending event, so the Thread won't run when the App is suspended:

_getBasketTimer.Dispose();

And start it when the app is resuming:

_getBasketTimer = new Timer(getBasketCallback, null, 5000, Timeout.Infinite);

Upvotes: 4

Views: 559

Answers (2)

Romasz
Romasz

Reputation: 29792

If you want to run a something on a thread in intervals (also on thread other than UI one), you may use System.Threading.Timer. A sample can look like this:

System.Threading.Timer myTimer = new System.Threading.Timer(async (state) => { if (UserLoggedIn) await Task.Delay(1000); }, null, 0, 5 * 1000);

Note that if you would like to access UI elements from timer's Callback, then you will have to use Dispatcher.

Also don't forget to stop timers/cancel tasks once your app gets suspended, and resume them on resuming event, if still needed.

Upvotes: 1

Jon
Jon

Reputation: 2891

Its hard to tell without seeing more code, but you probably need to wrap your loop in a new thread to get it off the UI thread:

 Task.Run(async () =>
            {
               while(UserLoggedIn)
               {
                  await Networking.getBasket();
                  await Task.Delay(5000);
               }
            });

Upvotes: 2

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