Re: Trouble retrieving selection from NSArrayController
Re: Trouble retrieving selection from NSArrayController
- Subject: Re: Trouble retrieving selection from NSArrayController
- From: Quincey Morris <email@hidden>
- Date: Tue, 22 Feb 2011 15:31:19 -0800
On Feb 22, 2011, at 15:04, Ayers, Joseph wrote:
> I understood from Scott Stevensons book that in 32bit mode you had to declare the instance variables.
Nope, not for Core Data (not unless you need instance variables *of your own* to implement custom properties or for some other reason). Core Data doesn't use instance variables internally at all (for your properties, I mean). See:
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CoreData/Articles/cdAccessorMethods.html#//apple_ref/doc/uid/TP40002154-SW9
IMO, this documentation is slightly confusing. You can *EITHER* declare the properties for Core Data-supplied scalar accessor methods (TapeName, TapeDate, Notes, VideoClip) in a class extension -- Tapes () -- and use @dynamic for each one in your implementation *OR* declare them in a non-existent category -- Tapes (TapesAccessors), if you follow the documentation's pattern -- and avoid the need for @dynamic.
The documentation doesn't make it clear that there are 2 ways of doing it.
In the case of the add/remove accessors, you can't use @dynamic to tell the compiler about the Core Data-supplied methods, so you have to use the non-existent category technique.
With your current class definition, the instance variables will be ignored completely. They will be nil unless you put something in them manually, and if you do that they have no effect on the Core Data properties.
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