Question

大家好，我想获得数据库中提供的所有房间。下面是表格结构：

表室：

CREATE TABLE [dbo].[Room] (
    [ID]            INT           IDENTITY (1, 1) NOT NULL,
    [Title]         NVARCHAR (50) NOT NULL,

    PRIMARY KEY CLUSTERED ([ID] ASC),
);

餐桌预订：

CREATE TABLE [dbo].[Booking] (
    [ID]               INT            IDENTITY (1, 1) NOT NULL,
    [RoomID]           INT            NOT NULL,
    [DateFrom]         DATETIME       NOT NULL,
    [DateTo]           DATETIME       NOT NULL,

    PRIMARY KEY CLUSTERED ([ID] ASC),
    CONSTRAINT [FK_Booking_Room] FOREIGN KEY ([RoomID]) REFERENCES [dbo].[Room] ([ID]),

);

这就是我到目前为止所做的事情，这是不对的。

var a = _RoomService.GetRooms()
 .Where(a => a.ID <> (_BookingService.GetBookings()
 .Where((b => b.DateFrom > thisDate.DateFrom || 
              b.DateFrom < thisDate.DateFrom && 
              b.DateTo > thisDate.DateTo || 
              b.DateTo < thisDate.DateTo))
 .ToList());

我希望获得用户选择“从日期和到期日期”时可用的所有房间。谢谢你的期待。

修改

这是我取得的成绩，但仍然没有结果......

var roomsBooked = from b in _BookingService.GetBookings()
                               where (b.DateFrom <= thisDate.DateFrom) && (b.DateTo >= thisDate.DateFrom) ||
                               (b.DateFrom <= thisDate.DateTo) && (b.DateTo <= thisDate.DateTo) ||
                               (b.DateFrom >= thisDate.DateFrom) && (b.DateTo >= thisDate.DateTo)
                               select b;


var availableRooms = _RoomService.GetRooms().Where(a => roomsBooked.Any(b => b.RoomID != a.ID));

欢迎任何可以提供帮助的人。我从昨天开始一直在努力:(谢谢

Answer 1

var bookings = _BookingService.GetBookings()
        .Where((b => b.DateFrom > thisDate.DateFrom || 
               b.DateFrom < thisDate.DateFrom 
                     && b.DateTo > thisDate.DateTo 
                          || b.DateTo < thisDate.DateTo);

var a = _RoomService.GetRooms().Where(a => !bookings.Any(b=>b.RoomID == a.ID)).ToList());

Answer 2

以下是我为您准备的示例。它与@ AD.Net asnwer完全相同，除了我的是用LINQ编写的。我把它放在一个控制台应用程序中，如果感兴趣的话，你可以测试和玩，只需复制和粘贴。

以下是代码：

class Program
{
    public DateTime DateFrom { get; set; }
    public DateTime DateTo { get; set; }

    static void Main(string[] args)
    {
        Program p = new Program();
    }

    public Program()
    {
        var _BookingService = new List<Booking>()
        {
            new Booking() { ID = 100, RoomID = 1, DateFrom = new DateTime(2016, 5, 15), DateTo = new DateTime(2016, 5, 17)},
            new Booking() { ID = 200, RoomID = 2, DateFrom = new DateTime(2016, 5, 20), DateTo = new DateTime(2016, 5, 25) }
        };

        this.DateFrom = new DateTime(2016, 5, 14);
        this.DateTo = new DateTime(2016, 5, 27);

        var roomsBooked = from b in _BookingService
                          where
                                  ((this.DateFrom >= b.DateFrom) && (this.DateFrom <= b.DateTo)) ||
                                  ((this.DateTo >= b.DateFrom) && (this.DateTo <= b.DateTo)) ||
                                  ((this.DateFrom <= b.DateFrom) && (this.DateTo >= b.DateFrom) && (this.DateTo <= b.DateTo)) ||
                                  ((this.DateFrom >= b.DateFrom) && (this.DateFrom <= b.DateTo) && (this.DateTo >= b.DateTo)) ||
                                  ((this.DateFrom <= b.DateFrom) && (this.DateTo >= b.DateTo))
                            select b;


        var availableRooms = GetRooms().Where(r => !roomsBooked.Any(b => b.RoomID == r.ID));

        foreach (var room in availableRooms)
            Console.WriteLine($"{room.Title}");

        Console.ReadKey();

    }

    public List<Room> GetRooms()
    {
        return new List<Room>()
        {
            new Room() { ID = 1, Title = "Room 1" },
            new Room() { ID = 2, Title = "Room 3" }
        };
    }
}

public class Room
{
    public int ID { get; set; }
    public string Title { get; set; }

}
public class Booking
{
    public int ID { get; set; }
    public int RoomID { get; set; }
    public DateTime DateFrom { get; set; }
    public DateTime DateTo { get; set; }
}

您感兴趣的多汁部分就是这段代码：

var roomsBooked = from b in _BookingService
                          where
                                  ((this.DateFrom >= b.DateFrom) && (this.DateFrom <= b.DateTo)) ||
                                  ((this.DateTo >= b.DateFrom) && (this.DateTo <= b.DateTo)) ||
                                  ((this.DateFrom <= b.DateFrom) && (this.DateTo >= b.DateFrom) && (this.DateTo <= b.DateTo)) ||
                                  ((this.DateFrom >= b.DateFrom) && (this.DateFrom <= b.DateTo) && (this.DateTo >= b.DateTo)) ||
                                  ((this.DateFrom <= b.DateFrom) && (this.DateTo >= b.DateTo))
                            select b;


        var availableRooms = GetRooms().Where(r => !roomsBooked.Any(b => b.RoomID == r.ID));

上面的代码首先选择预订的所有房间，并将它们放在roomsBooked集合中。之后，我调用了GetRooms()函数，它将获得你的＆＃34;数据库＆＃34;中的所有房间。然后我执行where()过滤掉当前不在GetRooms()列表/集合中的roomsBooked的所有会议室。我希望这有点道理

LINQ查询到房间预订

2 个答案: