如有A、B、C、D、E 五张表，他们的关系可以由以下的sql语句体现出来
sql中这几张表的左连接查询为：
select * from A
left join B on A.bid=B.id
left join C on B.cid=C.id
left join D on C.did=D.id
left join E on D.eid=E.id
where 1=1
现在改为linq实现以上的sql语句，大侠们帮忙啊，我这样写报错：
- C# code
var query = from a in data.A join b in data.B on a.bid equals b.id into ab from r1 in ab.DefaultIfEmpty() join c in data.C on r1.cid equals c.id into bc from r2 in bc.DefaultIfEmpty() join d in data.D on r2.did equals d.id into cd from r3 in cd.DefaultIfEmpty() join e in data.E on r3.eid equals e.id into ce from r4 in ce.DefaultIfEmpty() select new Signature { Id = a.Id, Name = r1.Name, Pro = r2.Pro, IpAdd = r3.IpAdd }; IList<Signature> list = query.Take(pageSize).Skip((page - 1) * pageSize).ToList();//在这句报错 return list;具体的报错信息为：无法将类型为“Remotion.Linq.Clauses.JoinClause”的对象强制转换为类型“Remotion.linq.Clauses.FromClauseBase",引发了“System.InvalidCastException”类型的异常，
求大侠帮忙，急急急啊！！！
------解决方案--------------------------------------------------------
- C# code
var query = from a in data.A join b in data.B on a.bid equals b.id into ab from b in ab.DefaultIfEmpty() join c in data.C on b.cid equals c.id into bc from c in bc.DefaultIfEmpty() join d in data.D on c.did equals d.id into cd from d in cd.DefaultIfEmpty() join e in data.E on d.eid equals e.id into ce from e in ce.DefaultIfEmpty() select new Signature { Id = a.Id, Name = b==null?"":b.Name, Pro = c==null?"":c.Pro, IpAdd = d==null?"":d.IpAdd };