c# - linq连接错误

Question

我有这个 linq 查询:

var segreterie = from s in db.USR_Utenti join h in db.USR_Accounts
                     on new {s.ID, settings.GruppoSegreteria} 
                     equals new {h.USR_UtentiReference,h.ID_Gruppo} select s;

有这个问题:

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

我该如何解决？

Answer 1

这两种类型应该相同——这意味着它们需要与您使用匿名类型相同的属性名称。试试这个:

var segreterie = from s in db.USR_Utenti join h in db.USR_Accounts
                 on new {s.ID, Groups = settings.GruppoSegreteria} 
                 equals new {ID = h.USR_UtentiReference, Groups = h.ID_Gruppo}
                 select s;

假设 s.ID 和 h.USR_UtentiReference 具有相同的类型，并且 settings.GruppoSegreteria 和 h.ID_Gruppo 照样做。