在Windows Phone通讯簿中唯一标识联系人

Question

Consider the following situation:

• I save data from a random Contact X from the address book into Iso Storage
• I leave the application and modify Contact X in the address book
• Coming back to the application, how can I identify that Contact X from Iso Storage is the same as Contact X that I just modified in the address book?

My intention is to periodically copy a user's address book data into Iso Storage and then sync it with a server. I'm only doing READ operations, which are fully permitted, if given authorization.

The problem is that the Contact ID is a private field, and I cannot use Contact Stores (which have public IDs).

Also, WP Contacts don't have content rules, meaning you can have contact with no name, with 10 phone numbers, with no phone numbers, etc, so taking a piece of content as a unique identifier will not work since consistency is not guaranteed.

Hash Codes will also not work since the a modified object results in a modified has code.

Any help is much appreciated.

Answer 1

Found an answer - thanks to a related question posted here.

I decompiled the Microsoft.Phone DLL and it seems that Contact.GetHashCode actually returns the Contact.ID value. Behavior has been confirmed to work as expected on various devices and on the emulator.

All those people who consistently insist that developers should not be allowed access to information such as the contact ID - please bear in mind that users Contact Access permission can be denied in the marketplace. When I'm developing, I'm assuming the user fully understands what he's getting himself into, since I take the time and write a meaningful description and MS does good acceptance testing. If the user suddenly realities the app "breaks his privacy" IT'S NOT MY PROBLEM AS A DEVELOPER.

The last paragraph is motivated by the fact that I saw a couple of answers formulated something like "devs don't need these features, they break privacy".