Timer in UWP App which isn't linked to the UI

问题

I'm working on an UWP MVVM project and would like to implement an automatic logout system if the user interaction stops for a specific time.
Until now I'm using a DispatcherTimer to count backwards from 200 every second.

TimerLeave = 200;
var _dispatcherTimer = new DispatcherTimer();
_dispatcherTimer.Tick += dispatcherTimer_Tick;
_dispatcherTimer.Interval = new TimeSpan(0, 0, 1);

_dispatcherTimer.Start();

But because the DispatcherTimer is linked with the UI and I'm building a MVVM App, I'm looking for an alternative.
I searched a bit and found Run a background task on a timer. The problem is that this timer can only be set to run every 15 minutes, which is a little too long to automaticly logout a user in my case. I found no workaround to reduce the 15 minutes.
So my question is, is there any possibility to set up a timer in an UWP Project that isn't linked to the UI and can be set variable?

回答1:

Yes - you can for example use Timer class - though you must remember that it run on separate thread. Example:

private Timer timer;
public MainPage()
{        
    this.InitializeComponent();
    timer = new Timer(timerCallback, null, (int)TimeSpan.FromMinutes(1).TotalMilliseconds, Timeout.Infinite);
}

private async void timerCallback(object state)
{
    // do some work not connected with UI

    await Window.Current.CoreWindow.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
        () => {
            // do some work on UI here;
        });
}

Note that the work dispatched on UI dispatcher may not be processed right away - it depend on dispatcher's workload.

Also remember that this timer runs along with your app and won't work when app is suspended.

回答2:

I resolved this issue recently using a ThreadPoolTimer class.

ThreadPoolTimer timer = ThreadPoolTimer.CreatePeriodicTimer((t) =>
        {
            //do some work \ dispatch to UI thread as needed
        }, TimeSpan.FromMinutes(1));

At present I am not aware of any advantage of this over the Timer solution already posted, but it has functioned well.

回答3:

You may be right at your code but I have used threadpool timer instead of dispacher timer, after referring above blog.

If I talk about initial level I was using dispatcher timer for my app, what happens actually, it goes hang after every 2days of continuous standby. So I thought of threadpool timer as you are referring in this blog, but in threadpool it went hung in just 5-6 hours.

So as per my experience I think dispatcher timer is more preferable than threadpool timer.

It's just my experience of using it.

来源：https://stackoverflow.com/questions/34271100/timer-in-uwp-app-which-isnt-linked-to-the-ui

标签

timer

uwp