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Introduction to Key-Value Observing Programming Guide

Contents:

Organization of This Document

Key-value observing is a mechanism that allows objects to be notified of changes to specified properties of other objects.

In order to understand key-value observing, you should first read Key-Value Coding Programming Guide.

Organization of This Document

These concepts are covered in this programming topic:

• “What is Key-Value Observing?” provides an overview of the functionality provided by key-value observing.

• “Registering for Key-Value Observing” describes how to register and receive observation notifications.

• “Automatic Versus Manual Support” describes the difference between automatic and manual key-value observing, and how to implement both.

• “Registering Dependent Keys” explains how to specify that the value of a key is dependent on the value of another key.

• “Ensuring KVO Compliance” describes what your classes must implement to be key-value observing compliant.

• “Key-Value Observing Implementation Details ” describes how key-value observing is implemented.

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