[Q] dropTarget with Class extends MovieClip

programming flash
1

Dear all,

The following is a Class called ‘Ball’, just a drag and drop movie clip
I would like to check that …
if the Ball has been dropped on/over the OBJECT1.

But i don’t know how to write it in a class
The OBJECT1 is already created on root and named as ‘object1’

 
package {
 import flash.display.MovieClip;
 import flash.events.MouseEvent;
 private var holder:MovieClip = new MovieClip();
 public class Ball extends MovieClip {
  public function Ball() {
   this.buttonMode = true;
   this.addChild(holder);
   this.addEventListener(MouseEvent.MOUSE_DOWN, onDragHandler);
   this.addEventListener(MouseEvent.MOUSE_UP, onDropHandler);
  }
 }
 function onDragHandler(e:MouseEvent):void {
  this.startDrag();
 }
 function onDropHandler(e:MouseEvent):void {
  this.stopDrag();
  if (this.dropTarget == root.object1) {
   trace("Hit");
  }
 }
}

tried :
[COLOR=seagreen]if (this.dropTarget == root.object1) {[/COLOR]
[COLOR=seagreen]trace(“hit”);[/COLOR]
[COLOR=seagreen]}[/COLOR]
result:
[COLOR=red]1119: Access of possibly undefined property OBJECT1 through a reference with static type flash.display:DisplayObject.[/COLOR]

tried:
[COLOR=seagreen]if (this.dropTarget == MovieClip(root).object1) {[/COLOR]
[COLOR=seagreen]trace(“hit”);[/COLOR]
[COLOR=seagreen]}[/COLOR]
result:
[COLOR=red]nothing happened[/COLOR]