asp.net Gridview里添加汇总行

if (e.row.rowtype == datacontrolrowtype.datarow)
{
totalcash += convert.todecimal(databinder.eval(e.row.dataitem, "cash"));
totalunbalanced += convert.todecimal(databinder.eval(e.row.dataitem, "unbalanced"));
totalsettled += convert.todecimal(databinder.eval(e.row.dataitem, "settled"));
}
else if(e.row .rowtype ==datacontrolrowtype .footer )
{
e.row.cells[0].text = "合计";
e.row.cells[1].text = totalcash.tostring("0.00");
e.row.cells[2].text = totalunbalanced.tostring("0.00");
e.row.cells[3].text = totalsettled.tostring("0.00");
e.row.font.bold = true;
}