事件和侦听程序

事件和侦听程序概述

使用事件和侦听程序发送和响应消息。

事件和侦听程序概念

事件向所有注册的侦听程序广播通知，并将特定于事件的数据传递给侦听程序回调函数。

事件和侦听程序语法

这些代码示例说明如何定义事件和侦听程序

Event Access List

Specify a list of classes that can be notified of a specific event.

Event Attributes

Control access to events by setting event attributes.

实现侦听程序

Listener Callback Syntax

Specify listener callbacks using function handles.

Callback Execution

Errors in listener callbacks do not prevent execution of other listeners. However, the order of listener execution is not defined.

Listener Lifecycle

MATLAB manages the lifecycle of listeners. For greater control of listener lifecycle, constructor listener objects using the listener method instead of addlistener.

Determine If Event Has Listeners

You can determine if there are listeners defined for a specific event and event source.

属性侦听程序

侦听对属性值的更改

MATLAB 为所有属性定义了在执行 set 和 get 前后触发的事件。

Assignment When Property Value Is Unchanged

Prevent the triggering of property events when values do not change using the property AbortSet attribute.

事件和侦听程序的示例

Define Custom Event Data

Redefine the event data that MATLAB passes to listeners when an event is triggered.

Observe Changes to Property Values

Listeners can respond to changes in the value of properties using predefined property events.

Implement Property Set Listener

Listeners can respond to changes in property values before or after MATLAB assigns the value.

Techniques for Using Events and Listeners

This example shows how to enable and disable listener execution using context menus.

Restore Listeners

You can restore property listeners from the loadobj method.