将列与多个表LINQ连接

Question

有一个表我想与不同表中的不同列连接。

到目前为止，我就是这样做的

var purchData = (from a in db.AppRequest
join e in db.Employee on a.Req_By equals e.Id
join c in db.Company on e.CompanyId equals c.Id
join d in db.Designation on e.DesignId equals d.Id
join l in db.Master_Locations on a.Req_Location equals l.Id
join dep in db.Department on e.DepId equals dep.Id
join p in db.Purchase on a.Id equals p.Req_Id
join pi in db.PurchasingItems on p.Id equals pi.Purchase_Id
join pd in db.PurchasingDetails on p.Id equals pd.Purchase_Id
join pds in db.PurchasingDetailsSup on pd.Id equals pds.PurchasingDetails_Id
join s in db.M_Supplier on pds.Supp_Id equals s.Id
join payMethod in db.Master_PayMethods on s.Pay_Method equals payMethod.Id
join poNo in db.ApprovedPoNumbers on p.Id equals poNo.Purchase_Id
where a.Id == id && pds.IsApproved == true

在db.ApprovedPoNumbers表中有purchase_Id和Supplier_Id

在db.PurchasingDetailsSup表中有purchase_Id和Supplier_Id

所以我想知道这里的join poNo in db.ApprovedPoNumbers on p.Id equals poNo.Purchase_Id行我想加入db.ApprovedPoNumbers表purchase_Id，Supplier_Id与db.PurchasingDetailsSup表purchase_Id和Supplier_Id

Answer 1

您可以通过使用想要匹配的标准构建两个对象并在它们上使用equals运算符来实现这一点：

on new {poNo.purchase_Id, poNo.Supplied_Id} equals new {pds.purchase_Id, pds.Supplier_Id} into details