Canceling background task only makes it go suspended

Question

I unregister my task (I removed the If to make sure all tasks are removed.):

foreach (var taskA in BackgroundTaskRegistration.AllTasks)
{
    //if (taskA.Value.Name == exampleTaskName)
    {
        taskA.Value.Unregister(true);
    }
}

Then I try to recreate it, and check if it doesn't exist:

private async void LaunchBackground()
{
    await BackgroundExecutionManager.RequestAccessAsync();

    foreach (var taskA in BackgroundTaskRegistration.AllTasks)
    {
        if (taskA.Value.Name == exampleTaskName)
        {
            await new ApplicationTrigger().RequestAsync();
            return;
        }
    }

    var builder = new BackgroundTaskBuilder();

    builder.Name = exampleTaskName;
    builder.TaskEntryPoint = "Background.BackgroundTask";

    ApplicationTrigger _AppTrigger = new ApplicationTrigger();
    builder.SetTrigger(_AppTrigger);

    builder.Register();

    await _AppTrigger.RequestAsync();
}

My task now only a defferal and does some other stuff, releasing it when cancellled:

    public void Run(IBackgroundTaskInstance taskInstance)
    {
        _deferral = taskInstance.GetDeferral();
        taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);
        AddWatched();
    }

    private void OnCanceled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason)
    {
        _deferral.Complete();
    }

But when I try to cancel and unregister the task, it just goes suspended. When I launch it again, it behaves weridly (I think there are two instances of it now, which both try to do the same thing at the same time).

I would ideally like to be able to kill the background task instead of backgronuding it - or if that doesn't work, if the task is suspended it should be unsuspended instead of another one created AND the old one being unsuspended.

Answer 1

When you want to cancel, set a Boolean property in ApplicationSettings from your app. In your background task, periodically check this property during execution and if set, cancel the process.