Can'#t access children

1

I have a simple class to create some buttons:

package {
 import flash.display.*;
 import flash.events.*;
 
 public class ControlButton extends Sprite {
 
:  
public var _gryBtn:GreyButton = new GreyButton();
      
public function createButton(what:String, iIndex:Number, m:Number):void {
// add name - its the url of the iamge without the swf eg introduction, 1999, mar2001
_gryBtn.name=ref;

in my main file I have a function that creates the buttons:


var gryBtn:ControlButton = new ControlButton();
gryBtn.addEventListener(MouseEvent.CLICK, sceneBtnClicked);

WHen I press the button I can get the name out easily by going


function sceneBtnClicked(e:Event):void{
  trace( e.target.ref)
}

all works fine
Later on the code I want to loop through all these buttons but I can’t seem to get name to work


for (j:Number:0; j<this.container.numChildren, j++){
trace (this.container.getChildAt(j).ref);
}

brings up “access of possibly undefined property”
I do have other mcs etc within that container which don’t have a ref
but also trace (this.container.getChildAt(5).ref) doesn’t work and I know number 5 is one of the ones that does have a ref
How do I use the ref to target the buttons
thanks
E