C# WPF。如何过滤List<int>

Question

我有两个列表想要比较，然后过滤它。因此，如果list1包含1,2,3,4和list2 2,4，我想过滤列表，只留下1和3

HProDataContext db = new HProDataContext();


        List<int> _AllRoomsID = (from d in db.rooms select d.id).ToList();
        List<int> _ClosedRoomsID = (from d in db.checkinouts select d.roomid).ToList();

        for (int i = 0; i < _ClosedRoomsID.Count; i++)
        {
            if (_AllRoomsID.Contains(_ClosedRoomsID[i]) == true)
            {

            }
        }

Answer 1

var OpenRooms = AllRoomsID.Except(ClosedRoomsID);

或者，如果您不需要IEnumearble：

List<int> OpenRooms = AllRoomsID.Except(ClosedRoomsID).ToList();