iPhone Core Data: Property Persistance Durring Undo

Question

I've got a data model built in core data for the iPhone. I also have an NSUndoManager working for that model. The problem is that I have certain properties on an entity that i don't want affected back during an undo and other properties that I do want rolled back. Is this possible without drastically changing things. If so what is the best way to go about doing it.

Answer 1

After a little reading...

The NSUndoManager methods:

- (void)disableUndoRegistration
- (void)enableUndoRegistration

will work provided that the NSManagedObjectContext method

- (void)processPendingChanges

is called directly after.

For example you could add the following method on a managed object to set weather or not a change to a property should be added to the undo stack:

- (void)setColor:(UIColor *)aColor undo:(BOOL)shouldUndo{
    if (shouldUndo)
     [self setColor:aColor];
    else{
     NSManagedObjectContext *moc = self.managedObjectContext;

     [moc processPendingChanges];                  //Disable undo
     [moc.undoManager disableUndoRegistration];

     [self setColor:aColor];                       //Preform change

     [moc processPendingChanges];                  //Enable undo
     [moc.undoManager enableUndoRegistration];
    }
}

Note, if you have a bunch of changes that you don't want added to the undo stack, this might not be the most efficient way to do it.