linq关节类型推断无法调用"join"错误 [英] linq joint type inference failed to call 'join' error

问题描述

我有3个表User，TeamMember和Assessment，所有三个表都有user_id列，User通过userid与TeamMember链接，而TeamMember和Assessment与user_id(TeamMember)&评分者，已评分(评估)

i have 3 tables User, TeamMember and Assessment all three have the user_id column, User is linked to TeamMember by userid and TeamMember and Assessment are linked with user_id(TeamMember) & rater,rated(Assessment)

我正在尝试与此

          from a in db.Assessments
                         join u in db.Team_Members on a.rated equals u.user_id
                         join u2 in db.Team_Members on a.rater equals u2.user_id

抛出此错误

join子句中的表达式之一的类型不正确. 调用加入"时类型推断失败.

The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'Join'.

知道发生了什么吗?

推荐答案

您需要确保a.rated/u.user_id和a.rater/u2.user_id是同一类型

You need to make sure a.rated / u.user_id and a.rater / u2.user_id are the same type

这篇关于linq关节类型推断无法调用"join"错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！