KVC点键问题

Question

我创建了一个class:

@interface KVOGame : NSObject
@property (nonatomic, strong) NSString *name;
@property (nonatomic, strong) NSString *releaseDate;
@property (nonatomic, strong) KVOPlatform *platform;
@end

另一个是it属性:

@interface KVOPlatform : NSObject
@property (nonatomic, strong) NSString *platformName;
@property (nonatomic, strong) NSString *platformVersion;
@end

然后我尝试使用KVC获得"platformVersion"，像这样

@interface KVOViewController ()
@end
@implementation KVOViewController
- (void)viewDidLoad
{
    [super viewDidLoad];
    KVOGame *game = [[KVOGame alloc] init];
    game.name = @"Bayonetta";
    game.releaseDate = @"8.10.2009";
    game.platform.platformName = @"PS3, Xbox360";
    game.platform.platformVersion = @"all versions";
    NSString *identifier = @"platform.platformVersion";
    NSLog(@"%@", [game valueForKey:identifier]);
}

并出现错误导致崩溃:

由于未捕获异常'NSUnknownKeyException'而终止应用程序，原因:'[valueForUndefinedKey:]:该类不符合key platform.platformVersion的键值编码'

我做错了什么?

更新:valueForKeyPath:而不是valueForKey也不工作-崩溃无论如何

Answer 1

try NSLog(@"%@", [game valueForKeyPath:identifier]);

我假设永远不会创建game.platform。