Linq 分组（group by）后列变行

表一：

表二：

已知表一的List,想得到表二的结果：

var query = from c  in t.AsEnumerable()
                        group c by new {
                            pingming = c.Field<string>("品名"),
                            guige = c.Field<string>("规格")
                                        }
                            into s
                            select new
                            {
                                pingming = s.Select(p => p.Field<string>("品名")).First(),
                                shuliang = s.Sum(p => Convert.ToInt32(p.Field<string>("数量"))),
                                guige = s.Select(p => p.Field<string>("规格")).First(),
                                biaohao = string.Join(";",s.Select(p => p.Field<string>("表号")))
                            };

             DataTable tbl = tableA1.Clone();
             query.ToList().ForEach(p => tbl.Rows.Add(p.pingming, p.guige,p.biaohao,p.shuliang));

附：lamada：          
  var query = Templist.GroupBy(m => new { m.Id, m.FileName, m.Market, m.ShipId }).Select(gp => new  { gp.Key.Id, gp.Key.FileName,  gp.Key.Market, gp.Key.ShipId, Contactlist = string.Join("，", gp.Select(s => s.Contact).ToArray()) });