在DATAGRID前加一列显示序号

<mx:DataGrid id="datagrid1" vScrollPolicy="off" width="600" height="{datagridheight-18}" dataProvider="{dataProvider}" change="changed1(datagrid1)" headerColor="#FFFFFF" focusIn="dispatchEvent({type: ‘focusIn‘ })" borderStyle="solid">
<mx:columns>
<mx:Array>
<mx:DataGridColumn headerText="序号" width="45" textAlign="center" resizable="false" sortable="false" cellRenderer="{Dansun_xh}" />
<mx:DataGridColumn headerText="日期" width="100" columnName="pzrq" />
</mx:Array>
</mx:columns>
</mx:DataGrid>

as 文件

//****************************************************************************
//Copyright (C) 2004
//****************************************************************************

import mx.core.UIComponent
import mx.controls.Text

class Dansun_xh extends UIComponent
{
var txt : MovieClip;
var getCellIndex : Function;

function Dansun_xh()
{
}

//创建对象
function createChildren(Void) : Void
{
txt = createClassObject(Text,"dsgText",5,{text:(getCellIndex().itemIndex+1)});
size();
}

// 设置大小
function size(Void) : Void
{
txt.setSize(layoutWidth, layoutHeight);
}

//设置变量
function setValue(str:String, item:Object, sel:Boolean) : Void
{
txt._visible = (item!=undefined);
txt.text =getCellIndex().itemIndex+1;
}

//返回高
function getPreferredHeight(Void) : Number
{
return 16;
}
//返回宽
function getPreferredWidth(Void) : Number
{
return 120;
}
}