DataTable Sum累加合计计算(DataRow 合并)

            //第一步，取得每行匹配的 行记录标题
            //可以是一个，也可以是组合，比如 车型+排量
            //**重要！必须定义
            string rowTitle = "车型,排量";

            string[] rowTitles = rowTitle.Split(',');
 
            //第二步，取得 行记录值 **重要！必须定义
            List<string> rowKeys = new List<string>();
            rowKeys.Add("飞度,1.4");
            rowKeys.Add("飞度,1.5");
            rowKeys.Add("雅阁,1.8");
 
            //检查异常,并生成行记录SQL
            List<string> rowSQL=new List<string>();

            if (rowTitles.Length != rowKeys[0].Split(',').Length)
            {
                throw new Exception("行记录不匹配");
            }
            else
            {
                for (int i = 0; i < rowKeys.Count; i++)
                {
                    string sql="";
                    for (int j = 0; j < rowTitles.Length; j++)
                    {
                        if (j>0)
                        {
                             sql+=" and " +rowTitles[j]+"='"+ rowKeys[i].Split(',')[j]+"'";
                        }
                        else
                        {
                             sql+= rowTitles[j]+"='"+ rowKeys[i].Split(',')[j]+"'";
                        }
                    }
                    rowSQL.Add(sql);
                }
            }




            //第三步，取得数据源DataTable

            List<DataColumn> dtcl=new List<DataColumn>();

            dtcl.Add(new DataColumn("车型"));
            dtcl.Add(new DataColumn("排量"));
            dtcl.Add(new DataColumn("销量"));
            dtcl.Add(new DataColumn("产量"));

            DataTable dt = new DataTable();

            for (int i = 0; i < dtcl.Count; i++)
            {
                dt.Columns.Add(dtcl[i]);
            }
 
 
            DataRow dr = dt.NewRow();
            dr["车型"] = "飞度";
            dr["排量"] = "1.4";
            dr["销量"] = "6";
            dr["产量"] = "5";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["车型"] = "飞度";
            dr["排量"] = "1.5";
            dr["销量"] = "23";
            dr["产量"] = "5";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["车型"] = "雅阁";
            dr["排量"] = "1.8";
            dr["销量"] = "10";
            dr["产量"] = "9";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["车型"] = "飞度";
            dr["排量"] = "1.5";
            dr["销量"] = "10";
            dr["产量"] = "15";
            dt.Rows.Add(dr);

            Dictionary<string, DataRow[]> rowValues=new  Dictionary<string, DataRow[]>();
            

            for (int i = 0; i < rowKeys.Count; i++)
            {
                rowValues.Add(rowKeys[i], dt.Select(rowSQL[i]));
            }

            //最后一步， 生成最终的合并DataTable
            DataTable dtEx = dt.Clone();

            //计算列
            List<string> calColumns = new List<string>();
            List<decimal> calColumnSums = new List<decimal>();

            calColumns.Add("销量");
            calColumns.Add("产量");
            calColumnSums.Add(0);
            calColumnSums.Add(0);

            for (int i = 0; i < rowValues.Count; i++)
            {
                DataRow drEx = SumRow(rowValues[rowKeys[i]], calColumns, calColumnSums);
 
                dtEx.ImportRow(drEx);
                for (int j = 0; j < calColumnSums.Count; j++)
                {
                    calColumnSums[j] = 0;
                }
            }