private THOK.Wms.AutomotiveSystems.Models.BillDetail[] SelectGroup(THOK.Wms.AutomotiveSystems.Models.BillDetail[] details) { THOK.Wms.AutomotiveSystems.Models.BillDetail[] billDetails = new THOK.Wms.AutomotiveSystems.Models.BillDetail[] { }; var bills = details.Select(r => new THOK.Wms.AutomotiveSystems.Models.BillDetail() { PieceQuantity = r.PieceQuantity+r.OperatePieceQuantity }) .ToArray(); return billDetails.Concat(bills).ToArray(); }