c# - Windows Phone 7: Establishing which page is being activated during the Application_Activated event -

i following general best practice principles of restoring persistent , none persistent state , objects when tombstoned app re-activated. can found in microsoft article

here

the samples show simple re-activation of main page of app. application has multiple pages (any of tombstoned , therfore re-activated) , each 1 binding different viewmodel object. know how ascertain page going activated can selectivly deserialize , recover correct viewmodel object page.

or best practice restore viewmodels or there design pattern this?

i have implemented simple pattern best described -

1. in application's activated , deactivated event, send message subscribing pages.
2. the pages subscribe message serialization/deserialization of data.

i using laurent bugnion's excellent mvvmlight library windows phone 7. here sample code illustrating message broadcast -

// ensure application state restored appropriately private void application_activated(object sender, activatedeventargs e) {    messenger.default.send(new notificationmessage<appevent>(appevent.activated, string.empty)); }  // ensure required application state persisted here. private void application_deactivated(object sender, deactivatedeventargs e) {    messenger.default.send(new notificationmessage<appevent>(appevent.deactivated, string.empty)); } 

within constructor of viewmodel class, setup subscription notification messages -

// register application event notifications messenger.default.register<notificationmessage<appevent>>(this, n => {    switch (n.content)    {       case appevent.deactivated:          // save state here          break;        case appevent.activate:          // restore state here          break;    } } 

i found strategy, data relevant page bound viewmodel saved , restored properly.

hth, indyfromoz