给表格添加合计列和合计行

 DataRow newDataRow = dt_Merge.NewRow();
            newDataRow["ZiZhiText"] = "合计";
            //循环dt
            foreach (DataRow item in dt_Merge.Rows)
            {   
                for (int j = 2; j < dt_Merge.Columns.Count; j++)
                {
                    if (string.IsNullOrEmpty(newDataRow[j].ToString()) == true)
                    {
                        newDataRow[j] = 0;
                    }
                    // 计算所有行的除合计的其他列合计值
                    newDataRow[j] = Convert.ToDecimal(newDataRow[j]) + Convert.ToDecimal(item[j]);
                }
            }
            dt_Merge.Rows.Add(newDataRow);