If the ActiveSync provider does not support real-time notification, how can changes and deletions of objects be detected?
Changes and deletions are detected by enumerating all objects in the store, then checking each one to see if it has changed. Objects appearing in the persisted list that are not enumerated are assumed to have been deleted. This checking process can be started before synchronization, or at a specified time interval. The interval is set in microseconds in STOREINFO::uTimerRes. Checking uses the same resources as the application and therefore cannot be started if the application is busy. To get around this, an ActiveSync provider can set STOREINFO::uTimerRes to 0. Then, whenever the ActiveSync status window receives focus — such as when the user clicks on it — it is reasonable to assume the application using the data is not busy and so the ActiveSync manager can start the enumeration.
