NEW IN 3.0:
• You can use pre-synchronous and post-asynchronous modes to handle events.
• You can register events at the file, list, and Web site levels.
• You can register multiple events per item.
• You can cancel pre-synchronous events and display custom error messages.
• You can register item events on generic lists, as well as on document libraries.
• You can declaratively register events per list type or content type.
• In addition to trapping standard list item events (for example, ItemAdding, ItemDeleting, or ItemUpdating), you can trap schema events (such as adding, removing, or updating columns), as well as Web site and site collection deletion
CREATING AN EVENTHANDLER:
• Create an event handler assembly by creating a class library. Add reference to the Microsoft.SharePoint.dll and inherit from the Microsoft.SharePoint.SPitemEventReceiver base class:
Public class SimpleEventHandler : SPItemEventReceiver, …
REGISTERING AN EVENT HANDLER:
•.Add
•By list template ID
•Declaratively by content type
NOTE: must be strongly named and registered in the GAC.