Adobe FLEX 2 - CREATING AND EXTENDING COMPONENTS Manual page 104

You could make the custom component slightly more reusable by using the
property to reference the TextArea control, rather than the
mx.core.Application.application
property, you can call the custom component from any other MXML component that
contains a TextArea control named myTAMain, as the following example shows:
<?xml version="1.0"?>
<!-- mxmlAdvanced/myComponents/StateComboBoxDirectRefParentObj.mxml -->
<mx:ComboBox xmlns:mx="http://www.adobe.com/2006/mxml"
close="handleCloseEvent(event);">
<mx:Script>
<![CDATA[
import flash.events.Event;
public function handleCloseEvent(eventObj:Event):void {
parentDocument.myTAMain.text=String(selectedIndex);
}
]]>
</mx:Script>
<mx:dataProvider>
<mx:Array>
<mx:String>AK</mx:String>
<mx:String>AL</mx:String>
</mx:Array>
</mx:dataProvider>
</mx:ComboBox>
Although these examples work, they require that the
property, and that MXML component knows that
example of a tightly coupled component. That is, the component is written for a specific
application and application structure, and it not easily reused in another application.
104 Creating Advanced MXML Components
static property. By using the
TextArea
. In this case, custom component is an
id
parentDocument
parentDocument
control has a predefined
id