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I would like to know what is the clean & correct way to notify my WP8 app that the ChannelUri has changed?

I read that i need to handle this in the ChannelUpdatedUri method. But i have a few queries here. Doesn't this require my app to be running all the time?

Second query is suppose i use ChannelUpdatedUri to listen for changes to the Uri. If there is a change will the app be notified as soon as it launches? Or will it be notified at a later time?

The trouble is if the app is not notified on launch then there is a possibility that it may re-register for a new channel uri before ChannelUpdatedUri is invoked. Isnt it?

Please help!

user1122549
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1 Answers1

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You'll only get notified of a change in the ChannelUri when you have the listener attached and the app running.

The best approach is to always check for the current Uri and pass it to the server when the app starts. You could leave the listener attached for the lifetime of your app and get a new one if it's lost while the app is running but in reality it's far more likely that the channel will be dropped/disconnected when the phone isn't in use.

There is, of course, the scenario where a channelUri may expire when the app isn't in use but the utility of the app is primarily around sending notifications. Obviously you need the user to restart the app to get a new connection but you can't tell them to restart the app.
This is a generic problem: how do you tell someone that you can't talk to them?

The reality of this situation is that if you really need to tell someone to launch the app again you'll need another way to do it.

Unfortunately, it's not possible to get an updated channelUri from a background agent, but you could query your backend to see if you need one and then raise a toast to the user to prompt them to reopen the app. Or you could just update the tile from the agent when this happens.

Alternatively you'll need to send them the prompt in another way (e.g. email or SMS?) but this is reliant on you capturing and securely storing these details.

There is no perfect solution to this scenario other than creating an app that the user opens regularly regardless of whether there are notifications or not and simply having the notifications as an extra feature.

Matt Lacey
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  • I am still not sure how the ChannelUriUpdated works. For example, if the app registers for notification and receives a ChannelUri (say A). Now the user shuts down the app. The next time the app is launched, will the ChannelUri automatically start listening for Changes to the last registered Uri (A)? Kindly explain. – user1122549 Sep 24 '13 at 15:47
  • @user1122549 The ChannelUri is the URI that you send push notifications to. The phone will handle the receipt of notifications sent to the Uri. For the most part, once you've created a ChannelUri for your app it won't change very often. It is very unlikely to change while you're using the app (unless this coincides with you sending an invalid notification-which will cause the channel to expire.) You typically really only need to worry about the channel being changed when it's first created as it is this event/callback that will be triggered. – Matt Lacey Sep 24 '13 at 17:43
  • Thanks Matt! As per your response i am checking the validity of the Uri on app launch. I will test it and provide an update on how it goes. – user1122549 Oct 04 '13 at 04:58