kvc 是kvo的基础，是core data的基础，并不是说 单纯kvc比 直接用.访问好处多了多少， NSManagedObject *character; //Lets assume the core data object has been fetched.//Giving the object some values to save later.[character setValue:@"Sakura Kinomoto" forKey:@"characterName"];[character setValue:38 forKey:@"ownedCards"];//Fetching those values using KVC.NSString *sakura = [character valueForKey:@"characterName"];NSInteger numberOfClowCards = [character valueForKey:@"ownedCards"];

 Key-value coding is a fundamental technology when working with key-value observing, Cocoa bindings, Core Data, and making your application AppleScript-able. You are expected to be familiar with the basics of Cocoa development and the Objective-C language.