Binding to a class method in Cocoa?

If I have a method like:

@interface CharacterSet
    + (NSArray *)allCharacterSets;
@end

Can I bind to it using Cocoa bindings?

I'm trying to hook up an NSComboBox's content values to it. When I enter CharacterSet.allCharacterSets into the "Model Key Path" field in IB, it doesn't work, saying:

[ addObserver: forKeyPath:@"CharacterSet.allCharacterSets" options:0x0 context:0x200275b80] was sent to an object that 开发者_运维知识库is not KVC-compliant for the "CharacterSet" property.

I'm not sure what else to try. Currently I have to store the return value of allCharacterSets into an ivar in my custom window controller (or custom window) to make it work, which seems like an extra step I shouldn't have to take.

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I'm working on a huge application and the extra steps you mentioned were really pain in the ass for me. So I developed a small proxy class that handles class method bindings.

First I've added a small proxy class

@implementation INClassProxy

- (id)valueForUndefinedKey:(NSString *)key {
    return NSClassFromString(key);
}

@end

Then added a category accessor to NSApplication

- (id)classProxy {
    static INClassProxy *proxy = nil;
    if (proxy == nil)
        proxy = [[INClassProxy alloc] init];
    return proxy;
}

(I actually added this to my application delegate and implemented application:delegateHandlesKey:)

Now you are ready to bind class methods to the Application object, even in the interface builder, with the keyPath @"classProxy.CharacterSet.allCharacterSets".

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@cocoafan.. I realized in my effusive comment.. that the example I stated may not work unless you were to actually implement your GENIUS answer as I had chosen to… In order to make this mind-numbingly brilliant (as well as simple) magic even more generic and useful… I just created a basic class as you had described, but instead of categorizing (is that what it's called?) NSApplication, i did it on NSObject. Full example below…

@interface AZClassProxy : NSObject
@end
@interface NSObject (AZClassProxy)
- (id)classProxy;
@end

…

@implementation AZClassProxy
- (id) valueForUndefinedKey:(NSString*)k { return NSClassFromString(k); }
@end
@implementation NSObject (AZClassProxy)
- (id) classProxy { static AZClassProxy *prx = nil; return prx = prx ?: AZClassProxy.new; }
@end

Edit…  After like 2 days my simple mind folded trying to remember who this works, and why it's so wonderful.  I will keep posting here as I have to do things to remind myself of what this is, and why I should care..  So a basic example..

NSObject *WHATEVS = NSObject.new;
NSLog(@"%@", [[WHATEVS.classProxy valueForKey:@"NSColor"] redColor]);

LOGNSCalibratedRGBColorSpace 1 0 0 1