Overhead of "unlistened" Events?

programming flash
1

I’m wanting to override most properties (at least the display ones such as x, y, z, scale, alpha etc) of a class. Whenever one of those values changes, they will dispatch a custom event.

Especially with hundreds of items at once, this is likely to affect performance, especially on items that are constantly moving.

Will Events that are never listened to affect the performance anything? Is it mainly all the different listener functions that are what slow down?

Would this make any difference performance wise? (Mainly referring to the “hasEventListener” check)

public override function set x(new_x:Number)
{
   if (this.hasEventListener(ChangeEvent.X))
   {
      //Check if the event was canceled
      if (this.dispatchEvent(new ChangeEvent(ChangeEvent.X, new_x, _x)))
      {
         _x = new_x;
      }
      else 
      {
         //Cancelled. Do nothing.
      }
   }
   else
   {
      _x = new_x;
   }
}

I’m guessing at least there might be a slight improvement, since it doesn’t need to construct a new “Event” unless neede