Macromedia flex 2 Manual

40

Creating Custom Events

Using the Event metadata tag

You use the 

[Event]

 metadata tag to define events dispatched by a component so that the 

Flex compiler can recognize them as MXML tag attributes in an MXML file. You add the 

[Event]

 metadata tag in one of the following locations:

ActionScript components

Above the class definition, but within the package definition, so 

that the events are bound to the class and not a particular member of the class.

MXML components

In the 

<mx:Metadata>

 tag of an MXML file. 

The Event metadata keyword has the following syntax:

[Event(name=”eventName”, type=”package.eventType”)]

The 

argument specifies the name, including the package, of the event. The 

argument specifies the class that defines the event.

The following example identifies the 

enableChange

 event as an event that an ActionScript 

component can dispatch:

[Event(name="enableChange", type="myEvents.EnableChangeEvent")]
public class MyComponent extends TextArea
{

...

}

The following example shows the 

[Event]

 metadata tag within the 

<mx:Metadata>

 tag of an 

MXML file:

<?xml version="1.0"?>
<!-- events\myComponents\MyButton.mxml -->

<mx:Button xmlns:mx="http://www.adobe.com/2006/mxml" 
    click="dispatchEvent(new EnableChangeEvent('enableChanged'));">

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

    <mx:Metadata>
        [Event(name="enableChanged", type="myEvents.EnableChangeEvent")]
    </mx:Metadata>
    
</mx:Button>