实体框架&包括 [英] Entity Framework & Include

问题描述

所有
请帮助我在以下情况下使include（）工作：

All Please help me make include() work in the following case:

ctx.Messages
  .Include("Comments.CommentType")
  .Include("Comments.Owner")
  .Include("Comments.Message")
  .Where(m => m.RID == messageId)
  .SelectMany(m => m.Comments)
  .Where(c => c.CommentType.Id == commentTypeId)
  .ToList();

如何重写此查询？

PS我使用EF 3.5（不是4.0）

P.S. I'm using EF 3.5 (not 4.0)

推荐答案

这很可能与问题包含并加入。基本上归结为：包含仅在语句结尾处应用，并且由于加入，您的查询类型从 IQueryable< Message> 更改为的IQueryable<注释> 。

This is most likely related to an issue with Include and joins. Basically it comes down to this: Includes are only applied at the end of the statement, and due to joining, the type of your query changes from an IQueryable<Message> to an IQueryable<Comment>.

通过删除连接，它应该正确地包含导航属性。尝试以下内容：

By removing the join, it should correctly include the navigation properties. Try the following:

ctx.Comments
   .Include("CommentType")
   .Include("Owner")
   .Include("Message")
   .Where(c => c.Message.RID == messageId && c => c.CommentType.Id == commentTypeId)
   .ToList();

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