Windows phone 8 Fast Resume when Tombstoned - windows

Question

http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj735579%28v=vs.105%29.aspx
According to the document when I use fast resume in windows phone 8 I can resume my App from main tile.
But when my app is tombstoned ,
for example, mainPage can navigate to ->pageA can naviget to->PageB, I deactived the app from PageA, then the
app is tombstoned, when I click the Tile that navigate to PageB, it's strange that the app back to Page A .
How to fix this problem?

Answer 1

It sounds like you are not saving the application state before it is tombstoned. There are 4 events that are fired for preserving application state:
These are related to completely closing and reopening the application (eg: Phone restart)
Application_Launching
Application_Closing
These are related to tombstoning (task switching)
Application_Activated
Application_Deactivated
It sounds like what you need is the second one relating to activating / deactivating. These methods are placed in the Applications *.cs file and allow you to preserve and reinstate the ViewModel when tombstoning.
This is an example:
private readonly string ModelKey = "Key";
private void Application_Deactivated(object sender, DeactivatedEventArgs e)
{
PhoneApplicationService.Current.State[ModelKey] = ViewModel;
}
private void Application_Activated(object sender, ActivatedEventArgs e)
{
if (PhoneApplicationService.Current.State.ContainsKey(ModelKey))
{
ViewModel = PhoneApplicationService.Current.State[ModelKey] as FeedViewModel;
RootFrame.DataContext = ViewModel;
}
}