IOS Key-Value Coding Programming Guide 1 -- Introduction

Source : Introduction

This document describes the NSKeyValueCoding informal protocol, which defines a mechanism allowing applications to access the properties of an object indirectly by name (or key), rather than directly through invocation of an accessor method or as instance variables.

這份文件描述了一個非正式的protocol(NSKeyValueCoding)，此份文件定義了一種機制，且這個機制允許應用程式透過name/key去間接地存取物件的屬性，而不是直接調用存取方法或實體變數

You should read this document to gain an understanding of how to use key-value coding in your applications and how to make your classes key-value coding compliant for interacting with other technologies. 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 theObjective-C language.

你應該詳讀這份文件，來增進你對KVC的認識，如何使用KVC在你的應用程式，如何讓你的類別具有KVC兼容並與其他技術互動，KVC是一個基礎的技術working with KVO, Cocoa bindins, Core Data,且讓你的應用程式AppleScript-able(蘋果腳本化),You are expected to be familiar with the basics of Cocoa development and theObjective-C language.

Organization of This Document

Key-Value Coding includes these articles:

• “What Is Key-Value Coding?” provides an overview of key-value coding.
• “Terminology” defines the terms commonly used to refer to an object’s properties.
• “Key-Value Coding Fundamentals” describes the basic principles required to use key-value coding.
• “Key-Value Coding Accessor Methods” describes the accessor methods your classes should implement.
• “Key-Value Validation” tells you how to implement property validation.
• “Ensuring KVC Compliance” describes the capabilities a class must implement to be key-value coding compliant.
• “Scalar and Structure Support” describes the data types supported by key-value coding.
• “Collection Operators” lists the available collection operators and describes their use.
• “Accessor Search Implementation Details” explains how the appropriate accessor method or instance variable is determined.
• “Describing Property Relationships” describes the use of meta-data to define the relationships between objects and their properties.
• “Performance Considerations” describes the performance considerations when using key-value coding.

See Also

There are other technologies, not covered in this document, that are related to key-value coding.

• Key-Value Observing Programming Guide describes the features of the key-value observing protocol that allows objects to observe changes in other objects.