C# 寄信語法(System.Net.Mail)

using System.Net.Mail;
public void  Send2(string szTo, string szSubject, string szBody, string szFrom, FileUpload Attachmentsurl)
 {
     //szTo 收件者 szSubject主旨  szBody內容 szFrom 寄件者 Attachmentsurl 附件 
      object[] mailtoadd = szTo.Split(',');
      for (int i = 0; i <= mailtoadd.Length - 1; i++)
      {
           MailAddress from = new MailAddress("寄件者", "收到後要顯示的名稱", System.Text.Encoding.UTF8);
           MailAddress to = new MailAddress(mailtoadd[i].ToString());
           MailMessage em = new MailMessage(from, to);
           em.SubjectEncoding = System.Text.Encoding.UTF8;
           em.BodyEncoding = Encoding.UTF8;
           //信件主題 
          em.Subject = szSubject;
          //內容 
          em.Body = szBody;
          if (Attachmentsurl.FileName != "")
          {
                    string path = @"" + 路徑 + Attachmentsurl.FileName.ToString();
                    Attachment data = new Attachment(path);
                    em.Attachments.Add(data);
          }
          em.IsBodyHtml = true;
          System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient();
          //登入帳號認證  
          client.Credentials = new System.Net.NetworkCredential("帳號", "密碼");
          // port 跟 host 是用gmail做例子其他非一樣
          client.Port = 587;
          client.Host = "smtp.gmail.com";
          //啟動SSL 
         client.EnableSsl = true;
          try
          {
               client.Send(em);


            }
            catch (Exception e)
           {
                  
            }
       }
  }