What is the "Session" in SystemTriggerType?

Question

      In API Windows.ApplicationModel.Background,  there are three SystemTriggerType as SessionStart, SessionConnected and SessionDisconnected. But, I don't understand and how to use?

Answer 1

Hi Jones,

The term session refers to a Windows user session. These events are available only to lockscreen apps. An app can figure out its lockscreen state using the lockscreen events.

-Jeff

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Jeff Sanders (MSFT)

Answer 2

          Thanks for your prompt reply. but still fail to trigger background task after add my app into lockscreen, is there any sample code for reference?

Answer 3

Hi Jones,

I took the BackgroundTaskSample and modified it to capture the Windows.ApplicationModel.Background.SystemTriggerType.sessionStart event

First in program.js, I modified the function registerSampleJavaScriptBackgroundTask and had it set the SystemTrigger to Windows.ApplicationModel.Background.SystemTriggerType.sessionStart.

Then I modified the UI to dump some localSettings so I could see if the background task was being invoked.  I added this to initialize:          var localSettings = Windows.Storage.ApplicationData.current.localSettings;
        sdkSample.displayError(localSettings.values["loginfo"]);

 

Then I added this to backgroundtask.js to set a value so that I could tell if the systemTrigger was being called:

    var localSettings = Windows.Storage.ApplicationData.current.localSettings;
    localSettings.values["loginfo"] = "Background " + backgroundTask.taskInstance.task.name + " Starting...";

Finally I add the icons to the manifest  for Wide Logo, Badge Logo, Gave a short name and ensured Show Name was enabled, said that it was Toast Capable and Lock Screen Notifications I set to Badge and Title Text.

Then I started the app in the debugger and registered the JavaScript Sample background task.  (note the UI should show a blue 'undefined' text.  Then I quit the app and added it as the lockscreen app.  I logged off, logged back on and waited so that the background task to execute.  Then I start the app again and the 'Background' text appeared in the UI indicating that the startingEvent did indeed kick off when I logged on.

-Jeff

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Jeff Sanders (MSFT)

Answer 4

     Work it!! Thanks very much for your help!