////  main.m//  kvcdemo01////  Created by ganchaobo on 13-5-6.//  Copyright (c) 2013年 ganchaobo. All rights reserved.//#import 
     
      #import "student.h"#import "book.h"//直接访问void kvc1(){    student * stu=[[[student alloc] init] autorelease];    //间接访问    //先找getname方法，key _key    [stu setValue:@"zs" forKey:@"name"];    NSLog(@"%@",stu.name);    NSLog(@"%@",[stu valueForKey:@"name"]);}//直接访问,根据对象先找对象中setprice方法，如果找不到price，_pricevoid kvc2(){    student * stu=[[[student alloc] init] autorelease];    stu.bk=[[[book alloc] init] autorelease];    [stu.bk setValue:@1.5 forKey:@"price"];    NSLog(@"%f",[stu.bk price]);    NSLog(@"%f",[[stu.bk valueForKey:@"price"] floatValue]);}//设置多个keyvoid kvc3(){    student *stu=[[[student alloc] init] autorelease];    NSDictionary *dic=@{@"name":@"zs",@"age":@12};    [stu setValuesForKeysWithDictionary:dic];//设置多个key的值    NSDictionary *dic1=[stu dictionaryWithValuesForKeys:@[@"name",@"age"]];    NSLog(@"%@",dic1);}//keypath间接访问void kvc4(){    student *stu=[[[student alloc]init]autorelease];    stu.bk=[[[book alloc] init] autorelease];    //间接设置值    [stu setValue:@15 forKeyPath:@"bk.price"];    NSLog(@"%f",stu.bk.price);    NSLog(@"%f",[[stu valueForKeyPath:@"bk.price"]floatValue]);}void kvc5(){    student *stu=[[[student alloc]init]autorelease];    stu.name=@"mike";    student *stu1=[[[student alloc]init]autorelease];    stu1.name=@"jack";    student *stu2=[[[student alloc]init]autorelease];    stu2.name=@"jim";    NSArray *arr=@[stu,stu1,stu2];    NSArray *arr1=[arr valueForKeyPath:@"name"];    NSLog(@"%@",arr1);    }void kvc6(){        student *stu=[[[student alloc]init]autorelease];    stu.bk=[book bookwithprice:1.5];            student *stu1=[[[student alloc]init]autorelease];    stu1.bk=[book bookwithprice:1.6];        student *stu2=[[[student alloc]init]autorelease];    stu2.bk=[book bookwithprice:1.7];    NSArray *arr=@[stu1,stu2,stu];    NSArray *arr1= [arr valueForKeyPath:@"bk.price"];    NSLog(@"%@",arr1);    }void kvc7(){        student *stu=[[[student alloc]init]autorelease];        book *book1=[book bookwithprice:1.5];    book *book2=[book bookwithprice:1.6];    book *book3=[book bookwithprice:1.7];    stu.books=@[book1,book2,book3];   NSArray *arr= [stu.books valueForKeyPath:@"price"];    NSLog(@"%@",arr);    NSLog(@"%f",[[stu.books valueForKeyPath:@"@sum.price"]floatValue]);            NSLog(@"%i",[[stu.books valueForKeyPath:@"@count"] intValue]);}int main(int argc, const char * argv[]){    @autoreleasepool {                kvc7();            }    return 0;} www.shudanyu.com