前提：设置属性ShowFooter="True"方法一：使用SQL查询统计出合计值，在绑定GridView时让其结果赋于一个DataTable(全局变量)，然后在RowDataBound事件中
程序代码:
if (e.Row.RowType == DataControlRowType.Footer)
{
e.Row.Cells[0].Text = "合计";
e.Row.Cells[3].Text = dtSum.Rows[0][0].ToString();
e.Row.Cells[4].Text = dtSum.Rows[0][1].ToString();
e.Row.Cells[5].Text = dtSum.Rows[0][2].ToString();
e.Row.Cells[6].Text = dtSum.Rows[0][3].ToString();
e.Row.Cells[7].Text = dtSum.Rows[0][4].ToString();
e.Row.Cells[8].Text = dtSum.Rows[0][5].ToString();
e.Row.Cells[9].Text = dtSum.Rows[0][6].ToString();
e.Row.Cells[10].Text = dtSum.Rows[0][7].ToString();
e.Row.Cells[11].Text = dtSum.Rows[0][8].ToString();
}
其中dtSum是那个全局DataTable，在绑定GridView同时将SQL查询的结果赋给它；效果如下：

方法二、直接把对应列每一行的值相加(不做数据查询，在RowDataBound事件中运算)
int mysum1 = 0;
int mysum2 = 0;
protected void GridList_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow )
{
DataRowView myrows=(DataRowView)e.Row.DataItem;
mysum1 +=Convert .ToInt32 (myrows[2].ToString ());
mysum2 += Convert.ToInt32(myrows[3].ToString());
}
// 合计
if (e.Row.RowType == DataControlRowType.Footer)
{
e.Row.Cells[0].Text = "合计";
e.Row.Cells[1].Text = mysum1.ToString();
e.Row.Cells[2].Text = mysum2.ToString();
}
}