DataChangeEvent  - AS3 Flash

package
{
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import fl.data.DataProvider;
    import fl.events.DataChangeEvent;
    import fl.controls.DataGrid;
    import fl.controls.Button;
    
    public class DataChangeEventExample extends Sprite
    {
        private var dg:DataGrid;
        private var dp:DataProvider;
        private var names:Array = [ "Mary", "Bob", "Sue", "Joe" ];
        
        public function DataChangeEventExample() {
            dp = new DataProvider();
            dp.addEventListener(DataChangeEvent.DATA_CHANGE,dataChanged);
        
            dg = new DataGrid();
            dg.move(10,45);
            dg.setSize(300,250);
            dg.columns = [ "name", "phone", "email" ];
            addChild(dg);

            var addContactBtn:Button = new Button();
            addContactBtn.label = "Add Contact";
            addContactBtn.move(10,10);
            addContactBtn.addEventListener(MouseEvent.CLICK, addContact);
            addChild(addContactBtn);            
        }
        
        private function getRandomPhone():String {
            return randomDigit()+randomDigit()+randomDigit()+"-"+randomDigit()+randomDigit()+randomDigit()+"-"+randomDigit()+randomDigit()+randomDigit()+randomDigit();    
        }
        private function randomDigit():String {
            return String(Math.round(Math.random()*10)%10);    
        }
        private function getRandomName():String {
            return names[Math.round(Math.random()*names.length)%names.length];    
        }
        private function addContact(e:MouseEvent):void {
            var randomName:String = getRandomName()
            dp.addItem( { name: randomName, phone: getRandomPhone(), email: randomName + "@fictitious.com" } );
        }
        private function dataChanged(e:DataChangeEvent):void {
            var changedItems:Array = e.items;
            dg.addItem(changedItems[0]);
        }
    }
}