Mail Attachement Zip File With Password

string zipDirPath;
    string zipDirPath2;
    string outputFilePath;
    string outputFilePath2;



DataSet ds = new DataSet();
        DataTable dt = new DataTable();

try
{
       
dt = ds.Tables[0];
                //this.GridView1.DataSource = dt;
                //this.GridView1.DataBind();
                //string path = Server.MapPath("TempMailFiles\\") + DateTime.Now.ToString("yyyyMMddHHmmss") + ".csv"  ;
                string path = Server.MapPath("TempMailFiles\\") + DateTime.Now.AddMonths(-1).ToString("yyyy") + "年" + DateTime.Now.AddMonths(-1).ToString("MM") + "月" + "test.csv";
                FileStream fs = new FileStream(path,FileMode.OpenOrCreate,FileAccess.ReadWrite);
                //FileStream fs = new FileStream(@"D:\BenYang\MIS\APPortalWeb\SC\TempMailFiles\1.txt" ,FileMode.OpenOrCreate);
              
                StreamWriter sw = new StreamWriter(fs,Encoding.GetEncoding("big5"));
                sw.WriteLine("A,B,C,D");
                foreach(DataRow dw in dt.Rows)
                {
                    sw.WriteLine(Convert.ToString(dw["A"]) + "," + Convert.ToString(dw["B"]) + "," + Convert.ToString(dw["C"]) + "," + Convert.ToString(dw["D"]));
                }
              
                sw.Close();
                fs.Close();
              
                MailMessage mail = new MailMessage();
                mail.From = new MailAddress(test@test.com.tw);
                mail.To.Add("test@test.com.tw");
                //mail.To.Add("test@test.com.tw");
                //mail.CC.Add("test@test.com.tw");
                //set the content
                mail.SubjectEncoding = Encoding.GetEncoding("big5");
                mail.Subject = "請協助提供" + DateTime.Now.AddMonths(-1).ToString("yyyy") + "年" + DateTime.Now.AddMonths(-1).ToString("MM") + "月" + "test";
                mail.BodyEncoding = Encoding.GetEncoding("big5");
                mail.Body = "Dear\n\r";
                mail.Body += "檢附" + DateTime.Now.AddMonths(-1).ToString("yyyy") + "年" + DateTime.Now.AddMonths(-1).ToString("MM") + "月" + "test";
                mail.Body += "";
                //Attachment data = new Attachment(path, MediaTypeNames.Application.Octet);
                //todo zip the attachement file
                try
                {
                    zipDirPath = Server.MapPath("TempMailFiles\\");
                    zipDirPath2 = Server.MapPath("TempMailFiles2\\");
                    outputFilePath = DateTime.Now.AddMonths(-1).ToString("yyyy") + "年" + DateTime.Now.AddMonths(-1).ToString("MM") + "月" + "test.csv";
                    outputFilePath2 = DateTime.Now.AddMonths(-1).ToString("yyyy") + "年" + DateTime.Now.AddMonths(-1).ToString("MM") + "月" + "test.zip";
                    ZipFile(zipDirPath + outputFilePath, zipDirPath2 + outputFilePath2, 6, 4096);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                string mailAttachementFilePath = zipDirPath2 + outputFilePath2;
                Attachment data = new Attachment(mailAttachementFilePath, MediaTypeNames.Application.Octet);  //todo change path
                ContentDisposition disposition = data.ContentDisposition;
                disposition.CreationDate = System.IO.File.GetCreationTime(path);
                disposition.ModificationDate = System.IO.File.GetLastWriteTime(path);
                disposition.ReadDate = System.IO.File.GetLastAccessTime(path);
                mail.Attachments.Add(data);
                SmtpClient client = new SmtpClient("mail.xxx.com.tw",25);
                client.Credentials = CredentialCache.DefaultNetworkCredentials;
                client.Send(mail);    //todo test
                data.Dispose();
                Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "sendmail", "alert('Mail寄送完畢');", true);

}
catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            cn.Close();
            if (File.Exists(zipDirPath + outputFilePath))
            {
                File.Delete(zipDirPath + outputFilePath);
            }
            if (File.Exists(zipDirPath2 + outputFilePath2))
            {
                File.Delete(zipDirPath2 + outputFilePath2);
            }
        }




public void ZipFile(string FileToZip, string ZipedFile ,int CompressionLevel, int BlockSize)
    {
           if (! System.IO.File.Exists(FileToZip))
           {
            throw new System.IO.FileNotFoundException("The specified file " + FileToZip + " could not be found. Zipping aborderd");
           }
       
           System.IO.FileStream StreamToZip = new System.IO.FileStream(FileToZip,System.IO.FileMode.Open , System.IO.FileAccess.Read);
           System.IO.FileStream ZipFile = System.IO.File.Create(ZipedFile);
           ZipOutputStream ZipStream = new ZipOutputStream(ZipFile);
           ZipStream.Password = "7777";
           ZipEntry ZipEntry = new ZipEntry(FileToZip.Substring(FileToZip.LastIndexOf("\\")+1));
           ZipStream.PutNextEntry(ZipEntry);
           ZipStream.SetLevel(CompressionLevel);
           byte[] buffer = new byte[BlockSize];
           System.Int32 size =StreamToZip.Read(buffer,0,buffer.Length);
           ZipStream.Write(buffer,0,size);
           try
           {
            while (size < StreamToZip.Length)
            {
             int sizeRead =StreamToZip.Read(buffer,0,buffer.Length);
             ZipStream.Write(buffer,0,sizeRead);
             size += sizeRead;
            }
           }
           catch(System.Exception ex)
           {
            throw ex;
           }
           ZipStream.Finish();
           ZipStream.Close();
           StreamToZip.Close();
    }