问题
Does WP8 have any OS hook or callback (sync mechanism) I can implement to get a notification when a contact changes?
For example I'm running an application as a background agent, and a user randomly changes a contact's details. I want to get notified in my background engine so that I can do various operations.
I could always implement a periodic check (say every minute I read all contacts and check to see if there are any modifications - assuming I'm remembering the last configuration somehow). But this solution is not efficient for a large number of contacts, especially when I want the application to run on the low end phones.
回答1:
Windows Phone does not support any built in way for applications to be notified of contact changes.
As you've noted, the only way to do this would be to track the details and periodically look for differences. Yes, you'd have to do this with the app running (rather than a background agent) if you want to support WP7 devices with one 256MB of memory.
As an alternative and assuming that the user is syncing their contacts with their live.Windows account you could create an external service that periodically polls their live account (via http://msdn.microsoft.com/en-us/live/ff519582.aspx) for changes and then send a notification to the device/app regarding the change.
来源：https://stackoverflow.com/questions/15109852/callback-for-phone-contacts-modification