The document provides guidance on building Windows Phone 8.1 apps, focusing on handling application states such as launching, suspending, and resuming. It includes code snippets demonstrating how to manage application lifecycle events, including deferrals during suspension and actions on resumption. Additionally, it emphasizes the importance of preserving data and the current state when transitioning between different application states.

1. WinRT Apps
Building Apps for Windows Phone 8.1 Jump Start

6. NotRunning Running

7. sealed partial class App : Application
{
/// <summary>
/// Invoked when the application is launched normally by the end user.
/// </summary>
/// <param name="e">Details about the launch request and process.</param>
protected override async void OnLaunched(LaunchActivatedEventArgs e)
{
// How did the app exit the last time it was run (if at all)
ApplicationExecutionState previousState = e.PreviousExecutionState;
// What kind of launch is this?
ActivationKind activationKind = e.Kind;
// ...
NotRunning
Running
Suspended
Terminated
ClosedByUser
Launch
File
Protocol
VoiceCommand
Etc.

8. App is suspended
All code stopped
No timers tick
No events fire
Process still alive and in memory
Code has a chance to respond
(next slide)

9. sealed partial class App : Application
{
public App()
{
this.InitializeComponent();
this.Suspending += OnSuspending;
}
private async void OnSuspending(object sender, SuspendingEventArgs e)
{
// Ask for a deferral if you need to do async work
var deferral = e.SuspendingOperation.GetDeferral();
// TODO: whatever async work you need to do when suspending
deferral.Complete(); // Then mark the deferral complete
}

10. Same app is resumed
Same process, same
memory so values of
variables are intact
All code runs
Code has a chance to
respond...
Launch Back Switcher

11. sealed partial class App : Application
{
public App()
{
this.InitializeComponent();
this.Suspending += OnSuspending;
this.Resuming += OnResuming;
}
private void OnResuming(object sender, object e)
{
// TODO: whatever you need to do to resume your app
}

13. http://bit.ly/w8Resuming

14. Running

17. Terminated

21. App Data Local Folder
(or roaming folder for Data)
12:38
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Bob Brown
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Arthur Abbott
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CONTACTS
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Work
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Home
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Email
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CONTACTS
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State
Data

24. 24

25. 25

26. 26
LoadState(
Parameter,
null /* dictionary */
);

27. 27
SaveState(
dictionary
);
LoadState(
Parameter,
null /*dictionary*/
);

28. 28
SaveState(
dictionary
);
LoadState(
parameter,
dictionary
);

29. 29
SaveState(
dictionary
);
LoadState(
Parameter,
dictionary
);

30. 30
...
...

31. 31

33. http://aka.ms/Tsatr4

34. ©2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, Office, Azure, System Center, Dynamics and other product names are or may be registered trademarks and/or trademarks in the
U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft
must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after
the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.