今天用Linq查詢的時候，出現“此上下文僅支援基元型別或列舉型別。”

var query = from user in userService.Entities
                join role in roles on user.ID equals role.USER_ID
                select new {user};

解決的方法是把查詢調整下位置

var query = from role in roles
                        join user in userService.Entities on role.USER_ID equals user.ID
                        select new { user };