与语句体一个lambda前pression不能转换为nopCommerce一个前pression树

问题描述

我尝试创建一个LINQ在nopCommerce 3.0连接查询。我在LINQ连接两个表，写

I try to create a linq join query in the nopCommerce 3.0. i join two table in linq and write

在code成功。但在Visual Studio intellicence节目，如

the code successfully. but the visual studio intellicence shows the error like

的语句体一个lambda前pression不能转换为前pression树

请参见下面的

 var roles = _customerEventRoleRepository.Table.Where(c => c.EventId == selevent)
                   .Join
                   (
                      _customerRepository.Table,
                      cev => cev.CustomerId, c => c.Id,
                      (cev, c) =>
                      {
                          var cust = new CustomerEventRolesModel();

                          cust.Id = cev.Id;
                          cust.CustomerId = c.Id;
                          cust.Customer = c.Email;
                          cust.ContactName = c.GetAttribute<string>(SystemCustomerAttributeNames.FirstName);
                          cust.CompanyName = c.GetAttribute<string>(SystemCustomerAttributeNames.Company);
                          cust.Speaker = cev.IsSpeaker;
                          cust.Sponsor = cev.IsSponser;

                          return cust;
                      }
                    ).OrderBy(cev => cev.Customer).ToList();

但错误显示

请帮忙

推荐答案

该错误消息的究竟的它说什么。你有一个lambda前pression。它有一个说法的身体。与语句体一个lambda前pression不能转换为前pression树。但加入需要一个前pression树EF使用。你应该尝试与没有一个身体像一个lambda前pression更换您是否有什么：

The error message is exactly what it says. You have a lambda expression. It has a statement body. A lambda expression with a statement body can not be converted to an expression tree. But Join requires an expression tree to use with EF. You should try replacing what you have with a lambda expression that doesn't have a body like:

(cev, c) => new CustomerEventRolesModel {
                Id = cev.Id,
                CustomerId = c.Id
            }

等。

顺便说一句，

ContactName = c.GetAttribute<string>(SystemCustomerAttributeNames.FirstName)

会不会与EF工作。期。你最好弄清楚别的东西了。

will NOT work with EF. Period. You better figure something else out.

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