后台拼成的table，怎么统计行和列的合计？

 private void BindData_Detail()
        {
            StringBuilder sb = new StringBuilder();
            string subjectname = string.Empty;
            double dangqiang_zong = 0;
            double keyong_zong = 0;
            double shiji_zong = 0;
            double zhichu_zong = 0;
            obj1 = new BrReport.BaoBiaoModel();
            deptup_id = hid_deptup.Value;
            obj1.user_id = Common.SessionManager.Se_UserID.ToString();
            obj1.deptupid = hid_deptup.Value;
            obj1.year = dro_Year.SelectedItem.Text;
            obj1.subjectid = hid_Subject.Value;
            obj1.deptid = hid_dept.Value;
            if (txt_month1.Text != "")
                obj1.month1 = txt_month1.Text;
            else
                obj1.month1 = "1";
            if (txt_month2.Text != "")
                obj1.month2 = txt_month2.Text;
            else
                obj1.month2 = DateTime.Now.Month.ToString();
            DataTable dt_dept = re_Manage.getDeptBen(obj1.deptid,obj1.deptupid,Common.SessionManager.Se_UserID.ToString());
            DataTable dt_Subject = re_Manage.getSubject1(obj1.subjectid);
            BrBase brBase = new BrBase();
            sb.Append("<table cellspacing=\"1\" cellpadding=\"0\" class=\"List\"> ");
            //列
            sb.Append("<tr><td class=\"List_Item\" align=\"center\" rowspan=\"2\" noWrap>项目</td>");
            sb.Append("<td class=\"List_Item\" align=\"center\" colspan=\"4\">合计</td>");
            for (int i = 0; i < dt_dept.Rows.Count; i++)
            {
                sb.AppendFormat("<td noWrap class=\"List_Item\" align=\"center\" colspan=\"4\">{0}</td>", dt_dept.Rows[i]["dept_name"]);
            }
            sb.Append("</tr>");
            sb.Append("<tr>");
            sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >当前月预算</td>");
            sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >可用余额</td>");
            sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >支出金额</td>");
            sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >实际余额</td>");
            for (int i = 0; i < dt_dept.Rows.Count; i++)
            {
                sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >当前月预算</td>");
                sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >可用余额</td>");
                sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >支出金额</td>");
                sb.Append("<td noWrap class=\"List_Item\" align=\"center\" >实际余额</td>");
            }
            sb.Append("</tr>\r\n");
            //行
            for (int j = 0; j < dt_Subject.Rows.Count; j++)
            {
                subjectname = re_Manage.getSubjectByUparent(dt_Subject.Rows[j]["Subject_id"].ToString());
                sb.Append("<tr>");
                sb.AppendFormat("<td noWrap class=\"List_Item\">{0}</td>", subjectname);
                obj = re_Manage.obj_info_New1(dt_Subject.Rows[j]["subject_id"].ToString(), null, DateTime.Now.Month.ToString(),obj1);                //合计的四列
                sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", obj.dangqian);
                sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", obj.keyong);
                sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", obj.zichu);
                sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", obj.shiji);                dangqiang_zong = dangqiang_zong + obj.dangqian;
                keyong_zong = keyong_zong + obj.keyong;
                shiji_zong = shiji_zong + obj.shiji;
                zhichu_zong = zhichu_zong + obj.zichu;                //科目对应的机构预算
                for (int i = 0; i < dt_dept.Rows.Count; i++)
                {
                    obj = re_Manage.obj_info_New1(dt_Subject.Rows[j]["subject_id"].ToString(), dt_dept.Rows[i]["dept_id"].ToString(), DateTime.Now.Month.ToString(),obj1);
                    sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.dangqian);
                    sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.keyong);
                    sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.zichu);
                    sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.shiji);
                }
            }
            sb.Append("</tr>\r\n");
            sb.Append("<tr>");
            sb.AppendFormat("<td class=\"List_Item\" >{0}</td>", "合计");
            sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", dangqiang_zong);
            sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", keyong_zong);
            sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", zhichu_zong);
            sb.AppendFormat("<td class=\"List_Item\" align=\"center\" >{0}</td>", shiji_zong);
            for (int i = 0; i < dt_dept.Rows.Count; i++)
            {
                obj = re_Manage.obj_info_New1(null, dt_dept.Rows[i]["dept_id"].ToString(), DateTime.Now.Month.ToString(),obj1);
                sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.dangqian);
                sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.keyong);
                sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.zichu);
                sb.AppendFormat("<td class=\"List_Item\">{0}</td>", obj.shiji);
            }
            sb.Append("</tr>\r\n");
            sb.Append("</table>\r\n");            sHtml = sb.ToString();
        }
在左边有个合计，是合计后面一行的所有数，在下面也有个合计，是合计上面一列的，现在问题是数据都是循环的，有什么办法可以不看那个obj的值,直接统计一行或一列，请说的明白点阿，我对这后台拼table不熟,