Guid

#region 生成ID
public static string CreateGuid(int index)
    {
        //CAST(CAST(NEWID() AS BINARY(10)) + CAST(GETDATE() AS BINARY(6)) AS UNIQUEIDENTIFIER)
        byte[] guidArray = Guid.NewGuid().ToByteArray();
        DateTime now = DateTime.Now;
        DateTime baseDate = new DateTime(1900, 1, 1);
        TimeSpan days = new TimeSpan(now.Ticks - baseDate.Ticks);
        TimeSpan msecs = new TimeSpan(now.Ticks - (new DateTime(now.Year, now.Month, now.Day).Ticks));
        byte[] daysArray = BitConverter.GetBytes(days.Days);
        byte[] msecsArray = BitConverter.GetBytes((long)((msecs.TotalMilliseconds + index * 10) / 3.333333));
        Array.Copy(daysArray, 0, guidArray, 2, 2);
        //毫秒高位
        Array.Copy(msecsArray, 2, guidArray, 0, 2);
        //毫秒低位
        Array.Copy(msecsArray, 0, guidArray, 4, 2);
        return new System.Guid(guidArray).ToString();
    }
    /// <summary>
    /// 创建一个按时间排序的Guid
    /// </summary>
    /// <returns></returns>
public static string CreateGuid()
{
    //CAST(CAST(NEWID() AS BINARY(10)) + CAST(GETDATE() AS BINARY(6)) AS UNIQUEIDENTIFIER)
    byte[] guidArray = Guid.NewGuid().ToByteArray();
    DateTime now = DateTime.Now;
    DateTime baseDate = new DateTime(1900, 1, 1);
    TimeSpan days = new TimeSpan(now.Ticks - baseDate.Ticks);
    TimeSpan msecs = new TimeSpan(now.Ticks - (new DateTime(now.Year, now.Month, now.Day).Ticks));
    byte[] daysArray = BitConverter.GetBytes(days.Days);
    byte[] msecsArray = BitConverter.GetBytes((long)(msecs.TotalMilliseconds / 3.333333));
    Array.Copy(daysArray, 0, guidArray, 2, 2);
    //毫秒高位
    Array.Copy(msecsArray, 2, guidArray, 0, 2);
    //毫秒低位
    Array.Copy(msecsArray, 0, guidArray, 4, 2);
    return new System.Guid(guidArray).ToString();
}
public static DateTime GetDateTimeFromGuid(string strGuid)
{
    Guid guid = Guid.Parse(strGuid);
    DateTime baseDate = new DateTime(1900, 1, 1);
    byte[] daysArray = new byte[4];
    byte[] msecsArray = new byte[4];
    byte[] guidArray = guid.ToByteArray();
    // Copy the date parts of the guid to the respective byte arrays. 
    Array.Copy(guidArray, guidArray.Length - 6, daysArray, 2, 2);
    Array.Copy(guidArray, guidArray.Length - 4, msecsArray, 0, 4);
    // Reverse the arrays to put them into the appropriate order 
    Array.Reverse(daysArray);
    Array.Reverse(msecsArray);
    // Convert the bytes to ints 
    int days = BitConverter.ToInt32(daysArray, 0);
    int msecs = BitConverter.ToInt32(msecsArray, 0);
    DateTime date = baseDate.AddDays(days);
    date = date.AddMilliseconds(msecs * 3.333333);
    return date;
}