I'm using toast-notifications in my UWP-app (MSDN Notifcations)
Is there a way to make those toast-notifications non-dismissable, so the user can not delete it?
The scenario is that the users location gets tracked even if the app is in background and I'd like to keep a permanent toast-notification in the notification-center while tracking is active.
Technically you can do this by setting the scenario attribute of your toast to incomingCall. But it's (fortunately) against the Microsoft Design Guidelines to use this just for keeping your notification persistent on screen and your app will be rejected when you try to submit it to the store.
Another way would be removing all your application's notifications from the action center and send an updated notification periodically. But from a user perspective I would hardly discourage you from doing that, due it is a horrible user experience.
In fact, it is not possible right now, to keep a notification permanently on screen or in the action center and update it periodically. At //build 2016, Microsoft announced new notifications and tiles. Maybe this might be interesting for you. You can find more information here: https://channel9.msdn.com/Events/Build/2016/B803