将Guid转换成16位长的字符串

转自：在C#中生成唯一的字符串和数字 http://www.cnblogs.com/lcwzj/archive/2009/04/16/1436992.html 

///

/// Guid to string(16)
///

private static string GenerateGuid16String()
{
    return GenerateGuid16String(Guid.NewGuid());
}
///

/// Guid to string(16)
///

private static string GenerateGuid16String(Guid guid)
{
    long i = 1;
    foreach (byte b in guid.ToByteArray())
        i *= ((int)b + 1);
    return string.Format("{0:x}", i - DateTime.Now.Ticks);
}

 

插入DB测试：

 

CREATE TABLE [ShortGuid16] (
    [Pkid] [int] IDENTITY (1, 1) PRIMARY KEY NOT NULL ,
    [Guid16] [char] (16) NOT NULL ,
    [GuidInt] [uniqueidentifier] NOT NULL   
)

--truncate table ShortGuid16

select Guid16,GuidCount
from
(
  select Guid16,count(Guid16) as GuidCount
  from ShortGuid16
  group by Guid16
  --order by GuidCount desc
) as ShortGuid16Count
where GuidCount>1

--select count(1) from ShortGuid16

 

 

    public static void RunSnippet()
    {
        //Console.WriteLine(GenerateStringID());
        string strConn="server=.;uid=sa;pwd=0;database=NorthwindCN;";
        //ShortGuid16
        using(SqlConnection objConn=new SqlConnection(strConn))
        {
            string sqlInsert=" INSERT INTO [ShortGuid16]([Guid16], [GuidInt])VALUES(@Guid16,@GuidInt); ";
            SqlCommand oCmd=new SqlCommand(sqlInsert,objConn);
            //
            SqlParameter para1=new SqlParameter("@Guid16",SqlDbType.Char,16);
            oCmd.Parameters.Add(para1);
            //
            SqlParameter para2=new SqlParameter("@GuidInt",SqlDbType.UniqueIdentifier,16);
            oCmd.Parameters.Add(para2);           
            //
            Guid g;
            string guid16;
            objConn.Open();
            for(int i=0;i<1000000;i++)
            {
                g=Guid.NewGuid();
                guid16 = GenerateGuid16String(g);
                oCmd.Parameters["@Guid16"].Value=guid16;
                oCmd.Parameters["@GuidInt"].Value=g;
                int iRows=oCmd.ExecuteNonQuery();
                if(iRows==1)
                {
                    //Console.WriteLine(g.ToString() + "/t" + guid16);
                }
                else
                {
                    Console.WriteLine("Fail!");
                }
            }
            objConn.Close();
            oCmd.Dispose();
            objConn.Dispose();
        }
    }