如何在Renderer中设置属性 Renderer中设置属性的方法实例

package com.citigroup.presentation.csa
{
    import flash.events.mouseevent;

    import mx.controls.label;
    import mx.controls.advanceddatagridclasses.advanceddatagridheaderrenderer;
    import mx.core.uitextfield;
    import mx.events.flexevent;

    public class groupheaderrenderer extends advanceddatagridheaderrenderer
    {
        public var children:array=[];
        public var expand:boolean=true;
        private var l:uitextfield;
        public function groupheaderrenderer()
        {
            super();
            l=new uitextfield();
            l.text="[-]";
            l.addeventlistener(mouseevent.click,toggle);
                    addchild(l);
            this.addeventlistener(flexevent.creation_complete,init);

        }
        private function init(event:flexevent):void{
            if(expand){
                l.text="[-]";
            }else{
                l.text="[+]";
                togglechildren(false);
            }
            this.removeeventlistener(flexevent.creation_complete,init);
        }
        override public function set data(value:object):void{
            super.data = value;
            this.setstyle("color","0xf9f088");
            this.setstyle("fontweight","bold");
            this.setstyle("textalign","left");
        }
        override protected function updatedisplaylist(unscaledwidth:number, unscaledheight:number):void{
                    super.updatedisplaylist(unscaledwidth,unscaledheight);
            label.x=0;
            l.x=label.x+label.width;
                    l.y=label.y;
        }

        private function toggle(event:mouseevent):void{
            if(l.text=="[+]"){
                l.text="[-]";
                togglechildren(true);
            }else{
                l.text="[+]";
                togglechildren(false);
            }
        }
        private function togglechildren(visible:boolean):void{
            if(children.length<=1) return;
            for(var i:int=1;i<children.length;i++){
                children[i].visible=visible;
            }
        }
    }
} 

public function genadgcolumn(headertext:string,datafield:string,width:number=100):advanceddatagridcolumn{
                var col:advanceddatagridcolumn=new advanceddatagridcolumn();
                col.headertext=headertext;
                col.datafield=datafield;
                col.width=width;
                return col;
            }
            public function genadgcolumngroup(headertext:string,datafield:string,children:array,expand:boolean=true):advanceddatagridcolumngroup{
                var group:advanceddatagridcolumngroup=new advanceddatagridcolumngroup();
                group.headertext=headertext;
                group.datafield=datafield;
                <span style="color:#ff0000;">var cf:classfactory=new classfactory(groupheaderrenderer);
                cf.properties ={'children':children,'expand':expand};
                group.headerrenderer=cf;                 
                group.children=children;
                return group;
            }