willUndoChange
An identifier for a message about an undo manager preparing to perform an undo.
Declaration
static var willUndoChange: NotificationCenter.BaseMessageIdentifier<UndoManager.WillUndoChangeMessage> { get }Discussion
Use this identifier with NotificationCenter’s addObserver(of:for:using:) or messages(of:for:bufferSize:) methods to observe messages of type UndoManager.WillUndoChangeMessage.