Question

我一直在研究linq查询几个小时但没有让它工作。

我试图将某些数据列表与另一个数据列表进行比较，但我不知道为什么它没有按预期工作。

我有一个DbSet，Room有一个设施清单，每个设施都有自己的ID。

所以我的方法采用了facilityId的列表（IEnumerable），我想返回与设施列表相匹配的所有房间。

所以我认为我的查询看起来像这样：

var rooms = DbSet.Include("Facility").Where(room => room.Facility.All(facility => facilityIds.Contains(facility.Id)));

但是这个查询给了我比预期更多的结果。任何人都可以帮我解决这个疑问吗？

更新示例

            var filterIds = new int[] {1,2};

            var facilities1 = new List<Facility> {new Facility() {Id = 1}};
            var facilities2 = new List<Facility> {};
            var facilities3 = new List<Facility> {new Facility() {Id = 1}, new Facility() {Id = 2}};

            var basicData = new List<Room>()
            {
                new Room() {Id = 1, Facility = facilities1},
                new Room() {Id = 2, Facility = facilities2},
                new Room() {Id = 3, Facility = facilities1},
                new Room() {Id = 4, Facility = facilities3},
                new Room() {Id = 5, Facility = facilities1},
                new Room() {Id = 6, Facility = facilities1},
            };

            var result = basicData.Where(r => (!filterIds.Any() || r.Facility.All(f => filterIds.Contains(f.Id))));

这个查询给了我6个结果，而且我只期待Id 4的房间。

Answer 1

这会有用吗？

rooms.Where(
   room =>    room.Facilities.Any() 
           && filterIds.All(x => room.Facilities.Any(o => o.Id == x))
);

<强>更新更新了您的示例数据。按设施4的预期返回房间1,2。仅返回设施1,3,4,5,6的房间1：

小提琴：https://dotnetfiddle.net/b24FbF

嵌套的linq查询包含

1 个答案: