Re: Use of KVC Array operators
Re: Use of KVC Array operators
- Subject: Re: Use of KVC Array operators
- From: Eli Bach <email@hidden>
- Date: Fri, 12 Mar 2010 09:32:34 -0700
On Mar 12, 2010, at 5:37 AM, Alexander Spohr wrote:
> Am 12.03.2010 um 04:34 schrieb Eli Bach:
>
>> The operators mentioned on this page, particularly "@unionOfSets".
>>
>> <http://developer.apple.com/mac/library/documentation/cocoa/Conceptual/KeyValueCoding/Concepts/ArrayOperators.html>
>>
>> I have the following Core Data object's setup
>>
>> ClassA ClassB ClassC
>> relationA --> relationB --> relation C
>>
>> where each of the relations is a many to one [one class A, many class B, and one class B, many class C].
>> Not all ClassB's will have ClassC objects attached to them
>>
>> I have an instance of classA, and I want an NSArrayController with all the ClassC objects for all the ClassB objects that are related to that specific instance of ClassA, preferably in a way that uses KVO instead of programmatically updating with fetches/predicates/etc.
>>
>> What would be the right way to bind the NSArrayController, assuming the nib owner has an instance of classA:
>
> How about Owner.instanceOfA.relationB.relationC ?
> If you ask an array for a key path you get a new array containing the resulting objects.
> You don’t need any operators.
I'll try this, but I don't expect it to work, because there can be 0 or more relationB object's, and each of those object's can have 0 or more relationC objects, and just 'plain' dot syntax won't produce a superset of relationC objects (from my understanding of KVO and KVC).
Eli
>> ie:
>>
>> bind content set to
>>
>> File Owner.instanceOfA.?
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