public void OnRoomParticipated(RoomParticipatedDTO roomParticipatedDTO) { if (_httpToken.UserId == roomParticipatedDTO.UserId.ToString()) { var room = OtherRooms.Where(r => r.Id == roomParticipatedDTO.RoomId).FirstOrDefault(); ChangeData(delegate { MyRooms.Add(room); OtherRooms.Remove(room); }); } }