C# toastnotification: unable to handle toast activation (user interaction)

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C#

MVC

Hello,

i have problems handling/evaluating the user reaction (button pressed...) from a ToastNotification.

What I have tried:

Tried this code:

ToastContentBuilder tcb = new ToastContentBuilder();
		tcb.AddArgument("action", "viewConversation");
		tcb.AddArgument("conversationId", 9813);
		tcb.AddText("Installation will be executed in 2 minutes");
		tcb.AddAppLogoOverride(new Uri(PROGRAM_PATH + "LDNotifyIcon.png"), ToastGenericAppLogoCrop.Circle);
		tcb.AddHeroImage(new Uri(PROGRAM_PATH + "LDNotifyHero.png"));
		tcb.AddToastInput(new ToastSelectionBox("time")
		{
			DefaultSelectionBoxItemId = "60",
			Items =
			 {
			new ToastSelectionBoxItem("1", "1 minute"),
			new ToastSelectionBoxItem("5", "5 minutes"),
			new ToastSelectionBoxItem("10", "10 minutes"),
			new ToastSelectionBoxItem("60", "1 hour"),
			new ToastSelectionBoxItem("240", "4 hours")
			//new ToastSelectionBoxItem("1440", "1 day")
			 }
		});
		tcb.AddButton(new ToastButton()
			.SetContent("Start now")
			.AddArgument("action", "startNow")
			.SetBackgroundActivation());
		tcb.AddButton(new ToastButton()
			.SetContent("Snooze")
			.AddArgument("action", "snooze")
			.SetBackgroundActivation());
		tcb.SetToastScenario(ToastScenario.Reminder);
		tcb.GetToastContent();
		toast = new ToastNotification(tcb.GetXml());
		toast.Activated += HandleToastActivation;
		toast.Tag = "RebootNotifier";
		ToastNotificationManager.CreateToastNotifier().Show(toast);
				
		private static void HandleToastActivation(ToastNotification sender, object args)
        {
            Log("HandleToastActivation reached"); // writing to Logfile
        }

The toast shows up, but when i press "Snooze", the void "HandleToastActivation" is never reached.

Alternatively i tried in the Startup function:

ToastNotificationManagerCompat.OnActivated += toastArgs =>
        {
			// Obtain the arguments from the notification
			ToastArguments args = ToastArguments.Parse(toastArgs.Argument);
			string strAction = args.Get("action");

			// Obtain any user input (text boxes, menu selections) from the notification
			ValueSet userInput = toastArgs.UserInput;
			userInput.TryGetValue("time", out object oTime);
			...
		}

Again.. the code lines are never reached.

I have a wpf application, included a packaging project, finally the project will be published as an MXIS Installation package file.

Could anyone please help me how i can get/handle the user input from the toast notification?
That would be great
Thanks a lot in advance !