C# 如何使用Linq将数据连接到实体和WCF数据服务？

我有4个相关实体，如下所示：

LocalAgency<-0..1----1->Agency<-0..1----1->Organization<-0..1----1->Customer

var items = (from i in Context.LocalAgencies.Expand("Agency").Expand("Organization").Expand("Customer")
             where (String.IsNullOrEmpty(CustomerName) || i.Agency.Organization.Customer.CustomerName.Contains(CustomerName))
             select i).Skip(StartIndex).Take(PageSize).ToList<LocalAgency>();

var items = (from localAgency in Context.LocalAgencies
             join agency in Context.Agencies on localAgency.CustomerID equals agency.CustomerID
             join organization in Context.Organizations on localAgency.CustomerID equals organization.CustomerID
             join customer in Context.Customers on localAgency.CustomerID equals customer.CustomerID
             where (String.IsNullOrEmpty(CustomerName) || customer.CustomerName.Contains(CustomerName))
             select localAgency).Skip(StartIndex).Take(PageSize).ToList<LocalAgency>();

IQueryable<LocalAgency> items = Context.LocalAgencies;
items = items.Except(from i in items
                     where (String.IsNullOrEmpty(CustomerName) || i.Agency.Organization.Customer.CustomerName.Contains(CustomerName))
                     select i).Skip(StartIndex).Take(PageSize);

如果“连接”只有1级深度，这种方法就可以工作，但它无法获取导航属性的导航属性

然后，我尝试了一个

连接

，如下所示：

LocalAgency<-0..1----1->Agency<-0..1----1->Organization<-0..1----1->Customer

var items = (from i in Context.LocalAgencies.Expand("Agency").Expand("Organization").Expand("Customer")
             where (String.IsNullOrEmpty(CustomerName) || i.Agency.Organization.Customer.CustomerName.Contains(CustomerName))
             select i).Skip(StartIndex).Take(PageSize).ToList<LocalAgency>();

var items = (from localAgency in Context.LocalAgencies
             join agency in Context.Agencies on localAgency.CustomerID equals agency.CustomerID
             join organization in Context.Organizations on localAgency.CustomerID equals organization.CustomerID
             join customer in Context.Customers on localAgency.CustomerID equals customer.CustomerID
             where (String.IsNullOrEmpty(CustomerName) || customer.CustomerName.Contains(CustomerName))
             select localAgency).Skip(StartIndex).Take(PageSize).ToList<LocalAgency>();

IQueryable<LocalAgency> items = Context.LocalAgencies;
items = items.Except(from i in items
                     where (String.IsNullOrEmpty(CustomerName) || i.Agency.Organization.Customer.CustomerName.Contains(CustomerName))
                     select i).Skip(StartIndex).Take(PageSize);

但是，此实例中不支持除之外的

---

我错过了什么？我是否需要在

数据服务

端设置一些东西，以允许沿着定义的导航属性进行简单连接？

我在

扩展

上使用了错误的语法。我做了以下工作：

var items = (from i in Context.LocalAgencies.Expand("Agency").Expand("Agency/Organization").Expand("Agency/Organization/Customer")
where (String.IsNullOrEmpty(CustomerName) || i.Agency.Organization.Customer.CustomerName.Contains(CustomerName))
select i).Skip(StartIndex).Take(PageSize).ToList<LocalAgency>();

var items=（来自Context.LocalAgencies.Expand（“代理”）.Expand（“代理/组织”）.Expand（“代理/组织/客户”）
其中（String.IsNullOrEmpty（CustomerName）| i.Agency.Organization.Customer.CustomerName.Contains（CustomerName））
选择i）.Skip（开始索引）.Take（页面大小）.ToList（）；