How to detect system sleep or hibernate in metro app?

Question

We have a metro app newly built which has low level library will track user's location data. If system is in "SLEEP" or "HIBERNATE" mode. We need to 

stop the low level threads, and resume them when system resumes.

Is there some way to track system power status in C++/CX?

Answer 1

Hi,

According build session "Fundamentals of Metro style apps: how and when your app will run" (http://channel9.msdn.com/Events/BUILD/BUILD2011/APP-409T")

Before system query event is arrived, metro app should goes to "Suspend" first.

So you should handle your app work well when your metro app is under suspend state.

See more on 

http://msdn.microsoft.com/en-us/library/windows/apps/hh464925.aspx

Answer 2

thanks for your reply. I have already tested this...

I tried to register "suspend" and "resume" event handler. But when system hibernates then resumes they are not invoked.

However they can be invoked when I press "suspend the application" or "resume the application" button in VS.

Answer 3

Someone has tested suspend/resume callback when system sleep/hibernate?

Answer 4

Metro app has only 3 states.. running, suspended, not running..

You should be register the suspending event handler like this section.

http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh465115.aspx

And you can catch the event's type through SuspendingEventArgs maybe.

void MainPage::App_Suspending(Object^ sender, SuspendingEventArgs^ e)

Good luck.

Answer 5

What steps are you taking to hibernate the system? The events are firing as I would expect when using the charm bar to put my laptop to sleep or by using the physical power button. I'm using the Media capture using webcam sample with a few modifications to the ::Suspending and ::Resuming methods to test the functionality. I am launching it from the Start Screen and putting the system to sleep with the app in the forground.

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David Lamb

Answer 6

Hi Dong Yi,

According I ask MSFT via another thread http://social.msdn.microsoft.com/Forums/en-US/toolsforwinapps/thread/9a6f9c1b-49ea-485b-9f2b-6cce840d84b5/ 

Gearard point out some direction the "debugger" is why you could not get correct "suspend" and "resume" event trigger on your app.

So I do some test and summarize my result as follows:

1. When  leave app about 5 sec or trigger another app about 5 sec, the "suspend" event will called.
2. "Suspends"/"Resume" event will trigger automatically when you not attach debugger on release build. See "Star without Debugging" on "debug" tab.
3. If you using debugger, you only trigger "suspend" manually.
4. Sleep/Hibernate will trigger "Suspend" if your app is release version without debugger attach.

I hope it helps, since it already resolve my question for long time.

Evan Lin

Answer 7

thanks for all, i will try again

Answer 8

Hi Guys,

Look like Dong, Yi is right.

'thanks for your reply. I have already tested this... I tried to register "suspend" and "resume" event handler. But when system hibernates then resumes they are not invoked. However they can be invoked when I press "suspend the application" or "resume the application" button in VS.'

I have same issue, very simple to reproduce in laptop:

1. Subscribe to 'suspend/resume' events

2. Launch your app.

3. Close your laptop

4. Open laptop again, nothing happen. Sleep/Hibernate WILL NOT trigger 'suspend' events!

 I am sit on this problem already 2 days. Any another solution?

Thanks

- Rost

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;-)Rost

Answer 9

Hi, I met the same problem "But when system hibernates then resumes they are not invoked",

Is this resolved or have an officail response?

Answer 10

Hi Mountain2012,

The marked answer is correct: the debugger prevents apps from suspending (otherwise you couldn't debug them).

If you are having trouble with suspend/resume when not debugging then please post your question in a new thread.

--Rob

Answer 11

Thanks Rob.

I run the app in release mode, not debugging.

I find another page, it says system sleep/hibernate will not trigger suspend event.  This answer my question.

http://social.msdn.microsoft.com/Forums/en-US/winappswithhtml5/thread/9fb95fd9-fd7a-4f1d-a082-b7c105590a6b