Linq to Sql 左连接查询

 var query = from t0 in context.ExpressSendMaster
 join t1 in context.Supplier on t0.SupplierCode equals t1.SupplierCode
 join t2 in context.ExpressSendPackageRule on t0.AreaId equals t2.Id into t0_join
 from t0_t2 in t0_join.DefaultIfEmpty()
 where t0.Id == MasterId
 select new ExpressPackageOffLineModel
 {
 PackWeight = t0.Weight,
 SupplierCode = t1.SupplierCode,
 SupplierName = t1.Name,
 SendDate = t0.SendDate,
 OneselfNumber = t0.OneselfNumber,
 Memo = t0.Memo,
 GroupCheck = t0.AreaCode,
 GroupName = t0_t2.NumberType == null ? "" : t0_t2.NumberType,
 GroupId = t0_t2.Id == null ?  : t0_t2.Id,
 LimitWeight = t0_t2.LimitWeight == null ?  : t0_t2.LimitWeight
 };

 if (query.Count() <= )
 {
 model.HasError = true;
 model.ErrorMessage = "错误提示";
 return false;
 }

 model.PackWeight = query.First().PackWeight;
 model.SupplierCode = query.First().SupplierCode;
 model.SupplierName = query.First().SupplierName;
 model.SendDate = query.First().SendDate;
 model.OneselfNumber = query.First().OneselfNumber;
 model.GroupName = query.First().GroupName;
 model.Memo = query.First().Memo;
 model.GroupCheck = query.First().GroupCheck;
 model.GroupId = query.First().GroupId;
 model.LimitWeight = query.First().LimitWeight;