EF查询问题，新人求指点

有一个集合List cameraIndexCodeList，一个EF实体Device对应字段是cameraIndexCode
想要查出Device中不包含cameraIndexCodeList的那部分集合，用lambda表达式

 class Program
    {
        static void Main(string[] args)
        {
           var  cameraIndexCodeList = new List<Device>();
            var device1 = new Device
            {
                cameraIndexCode = "1",
                diceCode = 1
            };
            var device2 = new Device
            {
                cameraIndexCode = "2",
                diceCode = 2
            };
            cameraIndexCodeList.Add(device1);
            cameraIndexCodeList.Add(device2);
            Console.WriteLine("1:" + JsonConvert.SerializeObject(cameraIndexCodeList));
            var newCameraIndexCodeList =cameraIndexCodeList.Select(x=> new { diceCode = x.diceCode });
            Console.WriteLine("2:" + JsonConvert.SerializeObject(newCameraIndexCodeList));
            Console.ReadKey();

        }
    }

    class Device
    {
        public string cameraIndexCode { get; set; }
        public int diceCode { get; set; }
    }