Class problem

Hello !:beam:
Can someone explain me this :


class myclass{
   private var $x:Number;
   private var targetMC:MovieClip;
 
   public function myclass(mc:MovieClip, ix:Number){
      $x = ix;
      targetMC = mc;
   }
 
   public function drawLine():Void{
      trace($x);//return 100
      with(targetMC){
         trace($x);//return undefined
         lineStyle(1,0x000000,100);
         moveTo(0,100);
         lineTo($x,100);
      }
   }
}
 
//in fla file
var c:myclass = new myclass(this,100);
c.drawLine();

Why is it impossible to acces $x inside the “with” statement ?
I never had this kind of problem outside class…

thanks a lot !