LINQ 左右连接

LINQ 左右连接：DefaultIfEmpty()

incomeList = (from p in db.Incomes

                              join m in db.Items

                              on p.ItemID equals m.ID into tempResult

                              from m in tempResult.DefaultIfEmpty()

                              select new IncomeItem

                              {

                                  ID = p.ID,

                                  ItemID = p.ItemID,

                                  IncomeMoney = p.IncomeMoney,

                                  CreateTime = p.CreateTime,

                                  UpdateTime = p.UpdateTime,

                                  ItemCode = m.ItemCode,

                                  ItemName = m.ItemName

                              }).ToList();