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Re: Cocoa says not KVC compliant
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Re: Cocoa says not KVC compliant


  • Subject: Re: Cocoa says not KVC compliant
  • From: Nathan Vander Wilt <email@hidden>
  • Date: Wed, 2 Jul 2008 13:33:21 -0700

On Jul 2, 2008, at 10:13 AM, Milen Dzhumerov wrote:
I've run into a something I find strange. I've got a property declared as:

@property(readwrite, assign, nonatomic) CGImageRef image;
...

When I try to set it using KVC (e.g. [obj setValue:[NSValue valueWithPointer:image] forKeyPath:@"image"]), it says [<*ClassName* 0x133050> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key image.'


Keep in mind that the core KVC messages are -setValue:(id)forKey: and - (id)valueForKey:. That is, the KVC functions deal with values that are true Objective-C objects.

Your [NSValue valueWithPointer:] shows you are somewhat aware of this, but if you look at http://developer.apple.com/documentation/Cocoa/Conceptual/KeyValueCoding/Concepts/DataTypes.html you will see that neither a CGImageRef nor a plain old pointer (void*) are supported scalar types in KVC.

I may be wrong, but my understanding is that you will not be able to use KVC on this property, at least not without declaring the property type to be an NSValue*, which may or may not be an appropriate solution to your particular problem.

hope this helps,
-natevw
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References: 
 >Cocoa says not KVC compliant (From: Milen Dzhumerov <email@hidden>)

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