KVC访问非属性变量

kvcs是否可以访问非属性变量,答案是可以的.

@interface ModelDemo : NSObject
{
//@private
    NSString *demoString;
}
@end

ModelDemo *demo = [[ModelDemo alloc] init];
[demo setValue:@"Demo" forKey:@"demoString"];
NSLog(@"%@",[demo valueForKey:@"demoString"]);

不会出现crash.即使加上@private.同样可以访问.