using System.Web.Mail to send email

there are many demos for send a email with c sharp language .however,you will find that most of them will be failed because of SMTPServer.Especially,authorization is required.

Code
 1public void SendEMail()
 2        {
 3            MailMessage mail = new MailMessage();
 4            mail.Priority = MailPriority.High;
 5            mail.From = "cccc@gmail.com";
 6            mail.To = "cccc@163.com";
 7            mail.Subject = "Send EMail System Demo";
 8            mail.Body = "Just for test.";
 9            mail.BodyEncoding = Encoding.UTF8;
10
11            // authorization
12            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusing", 1);
13            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendemailaddress", mail.From);
14            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpuserreplyemailaddress", mail.From);
15            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpaccountname", "cccc@163.com");
16            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "cccc");
17            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1);
18            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserver", "smtp.163.com");
19
20            SmtpMail.SmtpServer = "smtp.163.com";
21            SmtpMail.Send(mail);
22        }
23        #endregion