Objective-C: correctly handling common properties between a subclass of NSControl and NSActionCell?

One of the things I've always doubted about is how to properly handle the relationship between a custom subclass NSControland a subclass NSCell. During my introduction to Cocoa, I saw him mention several times how a parent control provides many of the same methods, accessories, and mutators as implementing child cells / cells. For example, the class NSControland NSCellhave in their header files -isEnabledand -setEnabled::

NSControl.h

- (BOOL)isEnabled;
- (void)setEnabled:(BOOL)flag;

NSCell.h

- (BOOL)isEnabled;
- (void)setEnabled:(BOOL)flag;

I understand that the class NSControlprovides cover methods for most of the properties found in NSCell. I'm more interested in knowledge: how are they implemented? Or even better, how to implement your own properties of your subclasses? Obviously, only Apple engineers really know what is going on inside their frameworks, but I thought maybe someone could shed some light on the best way to imitate the Apple cover method in its purest form.

I am terribly versed in materials, so I will give an example of what I am saying. Let's say I subclassed NSControlas follows:

BSDToggleSwitch.h

#import "BSDToggleSwitchCell.h"

@interface BSDToggleSwitch : NSControl

@property (nonatomic, strong) BSDToggleSwitchCell *cell;
@property (nonatomic, assign) BOOL sharedProp;

@end

And I subclassed NSActionCell:

BSDToggleSwitchCell.h

#import "BSDToggleSwitch.h"

@interface BSDToggleSwitchCell : NSActionCell

@property (nonatomic, weak) BSDToggleSwitch *controlView;
@property (nonatomic, assign) BOOL sharedProp;

@end

As you can see, both of them have a property with a name sharedProp.

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, ( ):

• Cocoa . ( ):

  [self bind:@"sharedProp" toObject:self.cell withKeyPath:@"sharedProp" options:nil];
  

  , /? KVO/KVC/Bindings, , . ?
  
  

• . :

  - (void)setSharedProp:(BOOL)sharedProp
  {
      if ( sharedProp == _sharedProp )
          return;
  
      _sharedProp = sharedProp;
  
      [self.cell setSharedProp:sharedProp];
  }
  

  :

  - (void)setSharedProp:(BOOL)sharedProp
  {
      if ( sharedProp == _sharedProp )
          return;
  
      _sharedProp = sharedProp;
  
      [self.controlView setSharedProp:sharedProp];
  }
  

  , . , , ? , , .
  
  

• . :

  static void * const BSDPropertySyncContext = @"BSDPropertySyncContext";
  
  - (void)observeValueForKeyPath:(NSString *)keyPath 
                        ofObject:(id)object 
                          change:(NSDictionary *)change 
                         context:(void *)context
  {
      if ( context == BSDPropertySyncContext && [keyPath isEqualToString:@"sharedProp"] ) {
  
          BOOL newValue = [[change objectForKey:NSKeyValueChangeNewKey] boolValue];
  
          if ( newValue != self.sharedProp ) {
              [self setSharedProp:newValue];
          }
  
      } else {
          [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
      }
  }
  

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