创建一个外键，LINQ-to-SQL为您创建导航属性。然后每个Dealer都有一个DealerContacts集合，您可以选择、筛选和操作这些DealerContacts。

from contact in dealer.DealerContacts select contact

or

context.Dealers.Select(d => d.DealerContacts)

如果不使用导航属性，就会错过LINQ-to-SQL的一个主要好处——映射对象图的部分。

创建一个外键，LINQ-to-SQL为您创建导航属性。然后每个Dealer都有一个DealerContacts集合，您可以选择、筛选和操作这些DealerContacts。

from contact in dealer.DealerContacts select contact

or

context.Dealers.Select(d => d.DealerContacts)

如果不使用导航属性，就会错过LINQ-to-SQL的一个主要好处——映射对象图的部分。

实际上，在linq中，通常最好不要加入。当有导航属性时，一个非常简洁的方式来写你的linq语句是:

from dealer in db.Dealers
from contact in dealer.DealerContacts
select new { whatever you need from dealer or contact }

它转换为where子句:

SELECT <columns>
FROM Dealer, DealerContact
WHERE Dealer.DealerID = DealerContact.DealerID

var results = from c in db.Companies
              join cn in db.Countries on c.CountryID equals cn.ID
              join ct in db.Cities on c.CityID equals ct.ID
              join sect in db.Sectors on c.SectorID equals sect.ID
              where (c.CountryID == cn.ID) && (c.CityID == ct.ID) && (c.SectorID == company.SectorID) && (company.SectorID == sect.ID)
              select new { country = cn.Name, city = ct.Name, c.ID, c.Name, c.Address1, c.Address2, c.Address3, c.CountryID, c.CityID, c.Region, c.PostCode, c.Telephone, c.Website, c.SectorID, Status = (ContactStatus)c.StatusID, sector = sect.Name };


return results.ToList();

试试这个:

     var data =(from t1 in dataContext.Table1 join 
                 t2 in dataContext.Table2 on 
                 t1.field equals t2.field 
                 orderby t1.Id select t1).ToList(); 

使用Linq Join操作符:

var q =  from d in Dealer
         join dc in DealerConact on d.DealerID equals dc.DealerID
         select dc;