c# - LINQ to Entities 无法识别方法 'Int32 ToInt32(Boolean)'

Question

基本上，我试图将一组值返回给 GridView，它不满足数组中的任何值。但是，在尝试时我得到了

的错误

LINQ to Entities does not recognize the method 'Int32 ToInt32(Boolean)' method, and this method cannot be translated into a store expression.

这是我的代码:

        public List<Room> getAvailRoom()
    {
        //Sessions from Default Page
        DateTime checkedIn = Convert.ToDateTime(System.Web.HttpContext.Current.Session["checkIn"]);
        DateTime checkedOut = Convert.ToDateTime(System.Web.HttpContext.Current.Session["checkOut"]);

        //retrieves all the bookings which happen between two dates
        var booking = (from b in context.Booking
                         where b.departureDate >= checkedIn && b.arrivalDate <= checkedOut
                         select b);

        //Counts how many rooms are booked during those dates
        int countRooms = booking.Count();

        int[] bookings = new int[countRooms];
        foreach (var booktypes in booking)
        {

                for (int i = 0; i < countRooms; i++)
                {
                    //Addings the RoomIds to the array
                    bookings[i] = booktypes.RoomId;
                }

        }
        //Returns values that does not equal to any roomIds within the bookings array.
        return (from b in context.Room
                where b.roomId != Convert.ToInt32(bookings.Any())
                select b).ToList();
    }

知道我做错了什么吗？

Answer 1

我认为您确实在寻找一个Contains 查询:

 return (from b in context.Room
                where !bookings.Contains(b.roomId) 
                select b).ToList();

您的代码段有两个问题:

• Any() 返回一个 bool 值 - 这根本不是您想要的
• 您正在尝试在 SQL 领域中执行 Convert.ToInt32 - 没有等同于此(基本上 Linq to Entities 无法将这部分转换为 SQL 查询)，所以这行不通。