datagrid单元格如何改变字体颜色

CellColor.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Label xmlns:mx="http://www.adobe.com/2006/mxml" textAlign="right" >  
	<mx:Script><![CDATA[
		import mx.controls.DataGrid;
		import mx.controls.dataGridClasses.DataGridColumn;
		import mx.controls.listClasses.BaseListData;
		
		override public function set data(value:Object):void
		{
			super.data = value;
			var dg:DataGrid = this.owner as DataGrid;
			if(dg && data){
				var gdgc:DataGridColumn =
					dg.columns[listData.columnIndex] as DataGridColumn;
				if(data[gdgc.dataField]> 0){
					this.setStyle("color",0xCD0000);
				}
				if(data[gdgc.dataField] < 0){
					this.setStyle("color",0x006400);
				}
			}
		}
		
	]]></mx:Script>
</mx:Label>

在DataGridColumn的itemRenderer中引用 如itemRenderer="CellColor"