C#如何生成唯一订单号

/// <summary>  /// 生成唯一数  /// </summary>  public class UniqueData  {    private static object obj = new object();    private static int GuidInt { get { return Guid.NewGuid().GetHashCode(); } }    private static string GuidIntStr { get { return Math.Abs(GuidInt).ToString(); } }    /// <summary>    /// 生成    /// </summary>    /// <param name="mark">前缀</param>    /// <param name="timeType">时间精确类型 1 日,2 时,3 分，4 秒(默认) </param>    /// <param name="id">id 小于或等于0则随机生成id</param>    /// <returns></returns>    public static string Gener(string mark, int timeType = 4, int id = 0)    {      lock (obj)      {        var number = mark;        var ticks = (DateTime.Now.Ticks - GuidInt).ToString();        int fillCount = 0;//填充位数        number += GetTimeStr(timeType, out fillCount);        if (id > 0)        {          number += ticks.Substring(ticks.Length - (fillCount + 3)) + id.ToString().PadLeft(10, '0');        }        else        {          number += ticks.Substring(ticks.Length - (fillCount + 3)) + GuidIntStr.PadLeft(10, '0');        }        return number;      }    }    /// <summary>    /// 生成    /// </summary>    /// <param name="mark">前缀</param>    /// <param name="timeType">时间精确类型 1 日,2 时,3 分，4 秒(默认)</param>    /// <param name="id">id 小于或等于0则随机生成id</param>    /// <returns></returns>    public static string GenerLong(string mark, int timeType = 4, long id = 0)    {      lock (obj)      {        var number = mark;        var ticks = (DateTime.Now.Ticks - GuidInt).ToString();        int fillCount = 0;//填充位数        number += GetTimeStr(timeType, out fillCount);        if (id > 0)        {          number += ticks.Substring(ticks.Length - fillCount) + id.ToString().PadLeft(19, '0');        }        else        {          number += GuidIntStr.PadLeft(10, '0') + ticks.Substring(ticks.Length - (9 + fillCount));        }        return number;      }    }    /// <summary>    /// 获取时间字符串    /// </summary>    /// <param name="timeType">时间精确类型 1 日,2 时,3 分，4 秒(默认)</param>    /// <param name="fillCount">填充位数</param>    /// <returns></returns>    private static string GetTimeStr(int timeType, out int fillCount)    {      var time = DateTime.Now;      if (timeType == 1)      {        fillCount = 6;        return time.ToString("yyyyMMdd");      }      else if (timeType == 2)      {        fillCount = 4;        return time.ToString("yyyyMMddHH");      }      else if (timeType == 3)      {        fillCount = 2;        return time.ToString("yyyyMMddHHmm");      }      else      {        fillCount = 0;        return time.ToString("yyyyMMddHHmmss");      }    }  }