摘要： 之前的一篇文章介绍了实现Key-Value Coding的5种方法，但用的最多的还是基于NSKeyValueCoding协议的。本文介绍的都是基于这个前提的。key是啥？A key is a string that identifies a specific property of an object. Typically, a key corresponds to the name of anaccessor method or instance variable in the receiving object. Keys must use ASCII encoding, begin wit 阅读全文