C# 关于二进制序列化时的数据没法正常保存的问题

程序可以正常运行，但是无法保存数据

class Program
    {
        static void Main(string[] args)
        {

            Size size = new Size ();

            BinaryFormatter bf = new BinaryFormatter();

            using (FileStream fs = new FileStream("date.bin", FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                size.Bil = 4;
                bf.Serialize(fs, size);
                Console.WriteLine("成功写入！");
            }

            try
            {
                FileStream fs1 = new FileStream("date.bin", FileMode.OpenOrCreate, FileAccess.Read);

                size = (Size)bf.Deserialize(fs1);
                Console.WriteLine("ag.bil:" + size.Bil);


                Console.WriteLine("static: " + Size.bil + "   " + Size.m);
            }catch(System.Net.Sockets.SocketException ex) { Console.WriteLine(ex); }
            Console.ReadKey();
        }

[Serializable]
    class Size
    {

        public static int bil;
        public static string m;
        public int Bil
        {
            get { return bil; }
            set { bil = value; }
        }
        public string M
        {
            get { return m; }
            set { m=value; }
        }
    }

结果最后储存的文件！

有点不知所措了

    public static int bil;
    public static string m;
这里去掉static