When developing WP 8.1 Windows Runtime application, what’s the equivalent of the PhoneApplicationService.Activated and PhoneApplicationService.Deactivated events? It looks like PhoneApplicationService class is only available in Silverlight WP apps.
Application.Suspending event is not fired on Deactivated event (i.e. when I press Windows button).
You are right, under WinRT there is no Activated/Deactivated events. Your App can be Activated, but it's little different than in Silverlight. About the lifcycle you can read here at MSDN.
Your App will be Suspended just after you Navigate away from it. But - it's not working while you are debugging - more information here. When you run normally your App it will be suspended very fast after you hit Back/Start buttons.
About Navigation there is one thing you should be aware - when you Navigate away from the App, first OnNavigatedFrom is fired, then Suspended events (in the way you have subscribed them). But when you go back to your App - then Resuming events are fired, but OnNavigatedTo is not fired - reference:
Note On Windows Phone, OnNavigatedFrom() is called when the app is suspended. OnNavigatedTo() is not called when the app is resumed.
In some situations your App can be put into Not Running state. More again at Lifecycle at MSDN.
