[C#]用SharpZipLib压缩多个文件

private void simpleButton1_Click(object sender, EventArgs e)
{
    string dbpath = Application.StartupPath   @"\db";
    string backuppath=Application.StartupPath @"\backup";
    zipdbfile(dbpath, backuppath);
}

private void zipdbfile(string dbpath, string backuppath)
{
    ZipOutputStream ZipStream = null;
    Random rad=new Random();
    try
    {
        string[] filenames = Directory.GetFiles(dbpath);
        Crc32 crc = new Crc32();
        string temp = backuppath   "\\"   DateTime.Now.ToString("yyyy.mm.dd.hh.mm.ss")   ".bak";
        if (File.Exists(temp))
        {
            temp = backuppath   "\\"   DateTime.Now.ToString("yyyy.mm.dd.hh.mm.ss.")   rad.Next(0, 100)   ".bak";
        }
        ZipStream = new ZipOutputStream(File.Create(temp));
        foreach (string file in filenames)
        {
            FileStream fs = File.OpenRead(file);
            byte[] buffer = new byte[fs.Length];
            fs.Read(buffer, 0, buffer.Length);
            string files = file.Substring(file.LastIndexOf(@"\")).Split('\\')[1].ToString();
            ZipEntry entry = new ZipEntry(files);
            entry.DateTime = DateTime.Now;
            entry.Size = fs.Length;
            fs.Close();
            crc.Reset();
            crc.Update(buffer);
            entry.Crc = crc.Value;
            ZipStream.PutNextEntry(entry);
            ZipStream.Write(buffer, 0, buffer.Length);
        }
        ZipStream.Finish();
        ZipStream.Close();
    }
    catch (Exception ex)
    {
        XtraMessageBox.Show("备份失败:"   ex.Message, "友情提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
        if (ZipStream!=null)
        {
            ZipStream.Close();
        }
    }
}