private void Button1_Click(object sender, System.EventArgs e)
  {
  if(IsValid)
  {
   Label13.Text="Welcome "+ TextBox1.Text +" "+TextBox2.Text + ".You have successfully registered.";
   HttpCookie mycookie=new HttpCookie("WebShoppe","You have visited the WebShoppe Site.");
   mycookie.Expires=System.Convert.ToDateTime("12/12/2005");
   Response.Cookies.Add(mycookie);
   MailMessage msg = new MailMessage();
   StringWriter strwriter =new StringWriter();
   HtmlTextWriter htmltxtwriter =new HtmlTextWriter(strwriter);
   htmltxtwriter.RenderBeginTag("html"); 
   htmltxtwriter.RenderBeginTag("head");
   htmltxtwriter.RenderBeginTag("title");
   htmltxtwriter.Write("Thank You!");
   htmltxtwriter.RenderEndTag();
   htmltxtwriter.RenderEndTag();
   htmltxtwriter.RenderBeginTag("body");
   htmltxtwriter.WriteLine("Thank you for registering with WebShoppe Site!");
   htmltxtwriter.RenderEndTag();
   htmltxtwriter.RenderEndTag();
   msg.From ="

[email protected]"; //要用在126smtp中註冊過的郵箱,並和下面程式碼中的註冊名及密碼要相符
   msg.To=TextBox12.Text;
   msg.Bcc="[email protected]";
   msg.Subject="Thanks for registering";
   msg.Body=strwriter.ToString();
   msg.BodyFormat=MailFormat.Html;
   msg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1"); //確認需要認證 
   msg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "pangtianbing"); //設定在smtp中使用的使用者名稱 
   msg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "**********"); //設定在smtp中使用的密碼. 

   SmtpMail.SmtpServer="smtp.126.com";

   SmtpMail.Send(msg);
  }
  }