GridView自动求和、求平均值小计

转自清清月儿gridview72绝技，略有改动

前台：唯一的花头就是设置ShowFooter="True"

private double sum = 0;//取指定列的数据和，你要根据具体情况对待可能你要处理的是int
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            sum += Convert.ToInt32(DataBinder.Eval(e.Row.DataItem, "dateTimeAll").ToString());

        }

        else if (e.Row.RowType == DataControlRowType.Footer)
        {
            e.Row.Cells[5].Text = "总薪水为：";
            e.Row.Cells[6].Text = sum.ToString();
            e.Row.Cells[3].Text = "平均薪水为：";
            e.Row.Cells[4].Text = ((int)(sum / GridView1.Rows.Count)).ToString();
            
        }
    }