c# – 元组 – LINQ to Entities中仅支持无参数构造函数和初始值

参见英文答案 > How can I extract a list of Tuple from a specific table with Entity Framework / LINQ?????????????????????????????????????2个
我想从数据库加载元组列表.但是,当尝试如下.我收到一个错误“在LINQ to Entities中只支持无参数构造函数和初始值设定项”.

List<Tuple<string,DateTime?>> schdule = new List<Tuple<string,DateTime?>>();
schdule = Entities.ScheduleDates.Where(x => x.Code == cCode).Select(x => new Tuple<string,DateTime?>(x.Key,x.Time)).ToList<Tuple<string,DateTime?>>();

但是,通过使用匿名类型,我不会收到任何错误.

var tempSchedule = Entities.ScheduleDates.Where(x => x.Code == cCode).Select(x => new { x.Key,x.Time }).ToList();

为什么我面临上述错误.

SELECT someAlias.Key,someAlias.Time ...