Gridview获取列总值及平均值

比如获取第十列的总值
    int sum=0;
    for(int i=0;i<this.gridview.Rows.Count;i++)
    {
        GridViewRow row=this.gridview.row[i];
        sum+=Convert.ToInt32(row.cells[10].Text.ToString());
    }
    Response.Write(sum.ToString());//总值
    Response.Write((sum/this.gridview.Rows.Count).ToString());