Macromedia flex 2 Manual

Dispatching custom events

Once defined using the

[Event]

metadata tag, you can refer to the event in an MXML file, as

the following example shows:

<?xml version="1.0"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
xmlns:MyComp="myComponents.*" >

<mx:Script>
<![CDATA[
import myEvents.EnableChangeEvent;

    public function
    enableChangedListener(eventObj:EnableChangeEvent):void {
    // Handle event.
    }
  ]]>
</mx:Script>

<MyComp:MyButton enableChanged="myTA.text='got event';" />

<mx:TextArea id="myTA" />

</mx:Application>

If you do not identify an event with the

[Event]

metadata tag, the compiler generates an

error if you try to use the event name in MXML. The metadata for events is inherited from
the superclass, however, so you do not need to tag events that are already defined with the

[Event]

metadata tag in the superclass.

Dispatching an event

You use the

dispatchEvent()

method to dispatch an event. The

dispatchEvent()

method

has the following signature:

public dispatchEvent(event:Event):Boolean

This method requires an argument of type Event, which is the event object. The

dispatchEvent()

method initializes the

target

property of the event object with a reference

to the component dispatching the event.

You can create an event object and dispatch the event in a single statement, as the following
example shows:

dispatchEvent(new Event("click"));

You can also create an event object, initialize it, and then dispatch it, as the following example
shows:

var eventObj:EnableChangeEvent = new EnableChangeEvent("enableChange");