#import <Foundation/Foundation.h>   @interface Sample : NSObject {    SEL action;   id target;    } @property SEL action; @property (assign) id target;  -(void)addTarget:(id) t action:(SEL) s; -(void)sample_dosomthing;  @end 

#import "Sample.h"   @implementation Sample  @synthesize action; @synthesize target;   -(void)dealloc{   target = nil;   [super dealloc]; }  -(void)addTarget:(id) t action:(SEL) s{   self.action = s;   self.target = t; }   -(void)sample_dosomthing{      [self.target performSelector:self.action]; }  @end 

-(void)control_dosomthing{   NSLog(@"control_dosomthing"); }  - (void)viewDidLoad {   [super viewDidLoad];      Sample *sample1 = [Sample new];   [sample1 addTarget:self action:@selector(control_dosomthing)]; }