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Eventos

Definir y activar eventos; crear elementos de escucha que responden a eventos

Los eventos son emisiones de avisos que se transmiten cuando se produce algún cambio o acción que involucra a un objeto. Los elementos de escucha definen funciones que se ejecutan cuando se producen eventos específicos. Las clases pueden definir y activar eventos. MATLAB^® puede activar eventos predefinidos cuando el código accede a las propiedades de los objetos.

Funciones

`events`	Event names
`notify`	Notify listeners that event is occurring
`addlistener`	Create event listener bound to event source
`listener`	Create event listener without binding to event source
`event.hasListener`	Determine if listeners exist for event

Clases

`event.EventData`	Base class for event data
`event.ClassInstanceEvent`	Event data for `InstanceCreated` and `InstanceDestroyed` events
`event.listener`	Class defining listener objects
`event.PropertyEvent`	Data for property events
`event.proplistener`	Define listener object for property events

Temas

Eventos y elementos de escucha

Overview Events and Listeners
Use events and listeners to send and respond to messages.
Event and Listener Concepts
Events broadcast notifications to all registered listener and pass event-specific data to listener callback functions.
Events and Listeners Syntax
These code examples show how to define events and listeners.
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.

Implementación de elementos de escucha

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.

Elementos de escucha de propiedades

Listen for Changes to Property Values
MATLAB defines pre and post set and get events for all properties.
Assignment When Property Value Is Unchanged
Prevent the triggering of property events when values do not change using the property AbortSet attribute.

Muestras de eventos y elementos de escucha

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.