Sheet Notifications

NSWindow offers a set of notifications related to sheets, which it broadcasts on occurrences of a sheet opening or closing. Each notification is matched to a delegate method, so an NSWindow’s delegate is automatically registered for all notifications that it implements methods for.

NSWindowWillBeginSheetNotification is sent before a sheet is presented on a window and NSWindowDidEndSheetNotification after it is dismissed.

A window delegate should implement the following methods to receive the appropriate sheet notification:

It is important to note that a window’s delegate is not the same as the modal delegate specified as a parameter in the NSBegin...Alert calls. The modal delegate passed into the NSBegin...Alert calls is a delegate relationship that exists only until the sheet is dismissed.