var ld:Loader=new Loader();
var urlReq:URLRequest=new URLRequest("a.swf");
ld.contentLoadinfo.addEventListener(Event.Completed,onComp);
//为loader指定好域
ld.load(urlReq,new loadContext(ApplicationDomain.currentDomain));

function onCompleted(e:Event):void
{
     var cls:Class=ApplictionDomain.currentDomain.getDefination("com.naiking.panelView") as Class;
var view:PanelView=new cls;
    
//如果未指定域
则通过loader.contentLoadino.ApplictionDomain.currentDomain.getDefinition()
}