gistfile1.m

// In a UIView subclass:
@interface MySlider
@property CGFloat min, max;
@end
@implementation MySlider
-(void)setMin:(CGFloat)value {
  _min = value;
  [self setNeedsDisplay];
}
-(void)setMax:(CGFloat)value {
  _max = value;
  [self setNeedsDisplay];
}
... etc for setValue, setColor, setFoo.....
@end



// Another example, from an NSManagedObject subclass:

-(void)setTitle:(NSString *)title {
    [self willChangeValueForKey:@"title"];
    [self setPrimitiveTitle:title];
    [self didChangeValueForKey:@"title"];
    _needsSearchTextUpdating = YES;
}

-(void)setTextDescription:(NSString *)textDescription {
    [self willChangeValueForKey:@"textDescription"];
    [self setPrimitiveTextDescription:textDescription];
    [self didChangeValueForKey:@"textDescription"];
    _needsSearchTextUpdating = YES;
}