.NET 2.0 發送EMail郵件

protected void Button1_Click(object sender, EventArgs e)
    ...{
        System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage();
        //收件人
        message.To.Add(txtMailAddress.Text);
        //抄送
        foreach(string mailAddress in txtCopyAddress.Text.Split(','))
        ...{
            if (!string.IsNullOrEmpty(mailAddress))
            ...{
                message.CC.Add(mailAddress);
            }
        }        
        //主題
        message.Subject = txtSubject.Text;

        message.From = new System.Net.Mail.MailAddress(fromAddress);
        message.Body = txtMailContents.Text;
        //發送附件
        if (fulAttachment.HasFile)

  ...{
            System.Net.Mail.Attachment attachment = new System.Net.Mail.Attachment(fulAttachment.PostedFile.FileName);
            message.Attachments.Add(attachment);
        }
        System.Net.Mail.SmtpClIEnt smtp = new System.Net.Mail.SmtpClIEnt(txtSMTPAddress.Text);
        smtp.Credentials = new System.Net.NetworkCredential(txtUserName.Text,txtPassWord.Text);
        
        //smtp.usedefaultcredentials = true;
          
        try
        ...{            
            smtp.Send(message);
            lblReturnMessage.Text = "Mail Send Success!";
        }
        catch (System.Net.Mail.SmtpException ex)
        ...{
            lblReturnMessage.Text = "Send Error:" + ex.Message;
        }
     }