The following example shows how you can use the static UIDUtil.getUID() method to generate and retreive a unique identifier for an Object. The first time you click the Display UID button, an Alert control displays the generated UID and a string representation of the Object (yay ObjectUtil.toString()!). The second time you click the Display UID button, you’ll notice that a new parameter is added to the Object, mx_internal_uid
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/11/01/creating-unique-identifiers-for-objects-using-the-getuid-method/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout
="vertical"
        verticalAlign
="middle"
        backgroundColor
="white">

    
<mx:Script>
        
<![CDATA[
            import mx.controls.Alert;
            import mx.utils.ObjectUtil;
            import mx.utils.UIDUtil;

            private function displayUID():void {
                var text:String = ObjectUtil.toString(myObj);
                var title:String = UIDUtil.getUID(myObj);
                Alert.show(text, title);
            }
        
]]>
    
</mx:Script>

    
<mx:Object id="myObj" name="peter" site="flexexamples.com" />

    
<mx:ApplicationControlBar dock="true">
        
<mx:Button label="Display UID"
                click
="displayUID();" />
    
</mx:ApplicationControlBar>

</mx:Application>