PHP Class yii\base\Event

It encapsulates the parameters associated with an event. The [[sender]] property describes who raises the event. And the [[handled]] property indicates if the event is handled. If an event handler sets [[handled]] to be true, the rest of the uninvoked handlers will no longer be called to handle the event. Additionally, when attaching an event handler, extra data may be passed and be available via the [[data]] property when the event handler is invoked.

Since: 2.0

Author: Qiang Xue ([email protected])

Inheritance: extends Object

Show file Open project: yiisoft/yii2 Class Usage Examples

Public Properties

Property	Type	Description
$data		the data that is passed to [[Component::on()]] when attaching an event handler. Note that this varies according to which event handler is currently executing.
$handled		whether the event is handled. Defaults to false. When a handler sets this to be true, the event processing will stop and ignore the rest of the uninvoked event handlers.
$name		the event name. This property is set by [[Component::trigger()]] and Event::trigger. Event handlers may use this property to check what event it is handling.
$sender		the sender of this event. If not set, this property will be set as the object whose trigger() method is called. This property may also be a null when this event is a class-level event which is triggered in a static context.

Public Methods

Method	Description
hasHandlers ( string \| object $class, string $name ) : boolean	Returns a value indicating whether there is any handler attached to the specified class-level event.
off ( string $class, string $name, callable $handler = null ) : boolean	Detaches an event handler from a class-level event.
offAll ( )	Detaches all registered class-level event handlers.
on ( string $class, string $name, callable $handler, mixed $data = null, boolean $append = true )	Attaches an event handler to a class-level event.
trigger ( string \| object $class, string $name, Event $event = null )	Triggers a class-level event.

Method Details

hasHandlers() public static method

Note that this method will also check all parent classes to see if there is any handler attached to the named event.

public static hasHandlers ( string \| object $class, string $name ) : boolean
$class	string \| object	the object or the fully qualified class name specifying the class-level event.
$name	string	the event name.
return	boolean	whether there is any handler attached to the event.

off() public static method

This method is the opposite of Event::on.

offAll() public static method

Detaches all registered class-level event handlers.

on() public static method

When a class-level event is triggered, event handlers attached to that class and all parent classes will be invoked. For example, the following code attaches an event handler to ActiveRecord's afterInsert event: php Event::on(ActiveRecord::className(), ActiveRecord::EVENT_AFTER_INSERT, function ($event) { Yii::trace(get_class($event->sender) . ' is inserted.'); }); The handler will be invoked for EVERY successful ActiveRecord insertion. For more details about how to declare an event handler, please refer to [[Component::on()]].

trigger() public static method

This method will cause invocation of event handlers that are attached to the named event for the specified class and all its parent classes.

public static trigger ( string \| object $class, string $name, Event $event = null )
$class	string \| object	the object or the fully qualified class name specifying the class-level event.
$name	string	the event name.
$event	Event	the event parameter. If not set, a default [[Event]] object will be created.

Property Details

$data public property

the data that is passed to [[Component::on()]] when attaching an event handler. Note that this varies according to which event handler is currently executing.

public $data

$handled public property

whether the event is handled. Defaults to false. When a handler sets this to be true, the event processing will stop and ignore the rest of the uninvoked event handlers.

public $handled

$name public property

the event name. This property is set by [[Component::trigger()]] and Event::trigger. Event handlers may use this property to check what event it is handling.

public $name

$sender public property

the sender of this event. If not set, this property will be set as the object whose trigger() method is called. This property may also be a null when this event is a class-level event which is triggered in a static context.

public $sender

public static off ( string $class, string $name, callable $handler = null ) : boolean
$class	string	the fully qualified class name from which the event handler needs to be detached.
$name	string	the event name.
$handler	callable	the event handler to be removed. If it is `null`, all handlers attached to the named event will be removed.
return	boolean	whether a handler is found and detached.

public static on ( string $class, string $name, callable $handler, mixed $data = null, boolean $append = true )
$class	string	the fully qualified class name to which the event handler needs to attach.
$name	string	the event name.
$handler	callable	the event handler.
$data	mixed	the data to be passed to the event handler when the event is triggered. When the event handler is invoked, this data can be accessed via [[Event::data]].
$append	boolean	whether to append new event handler to the end of the existing handler list. If `false`, the new handler will be inserted at the beginning of the existing handler list.