LINQ在嵌套列表 - 选择所有标识的 [英] Linq on a nested List - select all Id's

问题描述

我有一个嵌套的列表中，这样的事情：

I have a nested list, something like this:

List<Hotel> Hotels;

public class Hotel
{
    List<RoomType> RoomType;
}

public class RoomType
{
    Room Room;
}

public class Room
{
    int RoomId;
}

这是一个有点令人费解，很抱歉想不出更好的样机模型。这个想法是，我有很多的酒店，每个酒店有很多房型，并承担各类型客房有且只有一个房间对象。

It's a little convoluted, sorry couldn't think of a better mockup model. The Idea is that I have many hotels, each hotels has many room types, and assume each room type has exactly one room object.

从酒店名单现在，我只想选择所有的 RoomId ..我困在这里，而试图巢所有名单。

Now from Hotels list, I just want to select all RoomId's.. I am stuck here, while trying to nest all list..

现在，我想这样的：

//cant do this some invalid error
int[] AllRoomIds = Hotels.selectMany(x => x.Rooms)
                       .selectMany(y => y.RoomType.Room.Id).Distinct().ToArray()

//cant do this - z doesnt have anything
int[] AllRoomIds = Hotels.selectMany(x => x.Rooms)
                         .selectMany(y => y.RoomType)
                         .select(z => z. 

我如何做到这一点吗？

访问所有项目的所有ID在嵌套列表..偶尔它抱怨的不能转换int值布尔值，我不知道这意味着什么...

Accessing all id's of all items in a nested list.. occasionally it complains of cannot convert int to boolean and I do not know what it means...

谢谢..希望问题是understanble

Thanks.. hope the question was understanble

推荐答案

当你上面贴真的层次没有多大意义，我（似乎RoomType和房间都向后），我会后一例如去用它：

While the hierarchy you posted above really doesn't make much sense to me (seems RoomType and Room are backwards), I'll post an example to go with it:

Hotels.SelectMany(h => h.RoomType)
      .Select(rt => rt.Room.Id)
      .Distinct()
      .ToArray();

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