On Apr 7, 2010, at 9:14 AM, David Catmull wrote: > How do I make a table view column show a sum calculated from Core Data Values? > > I have a Budget entity with a to-many relationship of BudgetItems. In a table > view listing my budgets, I want a column that displays the total of a > budget's items' amounts. > > I tried binding the column to ite...@sum.limit, but got this error: > Unknown.m:0: error: -[BudgetTests testBudgetSheet] : [<_NSFaultingMutableSet > 0x102e28500> addObserver:forKeyPath:options:context:] is not supported. Key > path: @sum.limit > ..so I take it the particular NSSet variant used by Core Data doesn't support > observing @sum. Or did I do that wrong?
Yes, because you are trying to observe an element of a set. Same goes for arrays. Instead, add an array controller whose content is bound to "items", and bind to arrangedObjects->@sum.limit. HTH, Keary Suska Esoteritech, Inc. "Demystifying technology for your home or business" _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
