Re: How hard is it to make a NSOrderedSetController?
Re: How hard is it to make a NSOrderedSetController?
- Subject: Re: How hard is it to make a NSOrderedSetController?
- From: Keary Suska <email@hidden>
- Date: Sat, 18 Feb 2017 17:06:03 -0700
> On Feb 18, 2017, at 4:44 PM, Daryle Walker <email@hidden> wrote:
>
> I’m using a NSValueTransformer object to convert my Core Data to-many ordered relationship from a NSOrderedSet to a NSArray so NSArrayController can use it. I just connected a NSButton to the controller’s “add:” action. I get this:
>
>> NSManagedObjects of entity 'Message' do not support -mutableArrayValueForKey: for the property ‘header'
>
> So it seems that the controller skips my converted value and tries to alter the property directly, which it can’t. I thought that the problem was that NSOrderedSet.array returns an array of funny proxies, but manually copying to a NSMutableArray and returning that didn’t work either. So it seems that I have to make custom actions to add objects, and hopefully the controller will see the changes.
>
> But I’m wondering if I should go nuclear and create the NSOrderedSetController that Apple should have done years ago. I don’t know how hard this’ll be. It would be a serving-side Binding class. It would inherit from NSObjectController since NSArrayController would have those extra NSArray/NSSet connection methods.
>
> Does the Bindings section of the Interface Builder section of Xcode hard-code the Bindings list, or will it create entries for custom Binding-capable classes? If the answer is no customization, then I would have to connect the NSManagedObject instance to the controller in code.
OTOH, it may be easier to implement a to-many accessor pattern for the attribute <https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/KeyValueCoding/DefiningCollectionMethods.html#//apple_ref/doc/uid/10000107i-CH17-SW1>. You may need to use a different key name to get prevent Core Data from interfering, say “headerAsArray” or whatever.
HTH,
Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"
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