Exchange web services: why is ItemId not constant?

Question

I write a small application, which should automatically process the emails from a public folder. For each email, we want to save some metadata, in a database.

I wan

Answer 1

you have to convert the EntryItemId to EWS unique item id then you can use as primary key to create an entry into the DB

Have a look at:

http://blogs.msdn.com/b/brijs/archive/2010/09/09/how-to-convert-exchange-item-s-entryid-to-ews-unique-itemid-via-ews-managed-api-convertid-call.aspx