prevent outlook from deleting recurring event

Question

I have a plugin which syncs read-only shared calendars in Outlook with our collaboration system. I need to make sure the user cannot delete any appointments in these read-only calendars. It's possible to attach an event handler to any appointment in Outlook (this works) but it won't work for recurring events. Each occurrence in the recurrence pattern is a separate object in Outlook, and the app must attach an event handler to each of such objects. If the recurrence pattern is endless (which is quite popular for such appointments), the app should attach infinite number of event handlers.

Is it possible to attach an event handler to some of kind of a grouping object (if such entity exists) for all occurrences at once, or is there any other method of solving my task?

Answer 1

When an instance of a recurring appointment is deleted, the master appointment will be modified. You can intercept that change by subscribing to the AppointmentItem.Write event, whcih has the Cancel parameter.