简化代码as3

Question

我还在做一个有馅饼的项目。进入下一个级别。现在我有这个代码一直在重复，我试图让它变得简单，代码更少。所以这个代码重复了第2个到第12个。当我为pie_mc使用toString命令时，我得到一个错误，它不能用于MovieClip符号。我该如何解决这个问题？

if(counter == 2) {
  pie_mc = pie2_mc;
  //pie_mc = "pie" + counter.toString()+"_mc";
  pie_mc.visible = true;
  for (i=1; i <= counter; i++){
    partx_mc = "t"+ counter.toString()+"_p"+i.toString()+"_mc";
    pie_mc[partx_mc].alpha = 0.6;
    pie_mc[partx_mc].addEventListener(MouseEvent.CLICK, showPiepart);       
    }
}
if(counter == 3) {
  pie_mc = pie3_mc;
  //pie_mc = "pie" + counter.toString()+"_mc";
  pie_mc.visible = true;
  for (i=1; i <= counter; i++){
    partx_mc = "t"+ counter.toString()+"_p"+i.toString()+"_mc";
    pie_mc[partx_mc].alpha = 0.6;
    pie_mc[partx_mc].addEventListener(MouseEvent.CLICK, showPiepart);       
    }
}

in dutch：1067：Impliciete afgedwongen omzetting van een waarde van het type in een niet-gerelateerd type flash.display：MovieClip。 - 在MovieClip中隐式转换字符串类型的值。