public static class RandomHelper    {        /// <summary>        /// 随机数生成器        /// </summary>        public static Random Generator { get; } = new Random(SystemRandomInt());        /// <summary>        /// 使用RNGCryptoServiceProvider生成真正随机的二进制数据        /// </summary>        public static byte[] SystemRandomBytes()        {            byte[] bytes = System.Guid.NewGuid().ToByteArray();            return bytes;        }        /// <summary>        /// 使用RNGCryptoServiceProvider生成真正随机的整数        /// </summary>        public static int SystemRandomInt()        {            return BitConverter.ToInt32(SystemRandomBytes(), 0);        }        /// <summary>        /// 生成10位数的编号        /// </summary>        public static string GenerateSerial()        {            //把guid转换为两个long int            byte[] bytes = System.Guid.NewGuid().ToByteArray();            UInt64 high = System.BitConverter.ToUInt64(bytes, 0);            UInt64 low = System.BitConverter.ToUInt64(bytes, 8);            //转换为10位数字            UInt64 mixed = ((high ^ low) % 8999999999) + 1000000000;            return mixed.ToString();        }        public static string GenerateOrderId()        {            long id = DateTime.Now.Ticks - DateTime.Parse("2017/01/01").Ticks;            return id.ToString("D10");        }        /// <summary>        /// 生成随机字符串        /// </summary>        /// <param name="length">字符串长度</param>        /// <param name="chars">包含的字符，默认是a-zA-Z0-9</param>        /// <returns></returns>        public static string RandomString(int length, string chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")        {            var buffer = new char[length];            for (int n = 0; n < length; ++n)            {                buffer[n] = chars[Generator.Next(chars.Length)];            }            return new string(buffer);        }    }