linq group by 多条件并返回原数据。
(from p in qList group p by new { p.itemCode, p.City, p.VcCode } into g select new { q_count = g.Sum(p=>p.iSampleCount), q_price = g.Sum(p=>p.iPrice), q_amt = g.Sum(p=>p.iAmt), q_itemCode = //这里我想得到p.itemCode }).ToList();