asp.Net送信メール

   /// <summary>
            ///             
            /// </summary>
            /// <param name="subject">  </param>
            /// <param name="content">  </param>
            /// <param name="to">       </param>
            /// <param name="fromdesc">  ：</param>
            /// <returns></returns>
public static string SendEmail2(string subject, string content, string to, string fromdesc, string guid)
            {
                string result = "0";
                try
                {
                    content = "     ：<br />      ！<br />             ，               ：";

                    to = to.Trim();
                    MailMessage mailMessage = new MailMessage();
                    mailMessage.From = new MailAddress("[email protected]", fromdesc);
                    mailMessage.To.Add(to);
                    mailMessage.Subject =subject.Replace(" ","");
                    mailMessage.IsBodyHtml = true;
                    //mailMessage.Priority = MailPriority.High;
                    mailMessage.BodyEncoding = System.Text.Encoding.UTF8;
                    mailMessage.Body = content;
                    mailMessage.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;

                    SmtpClient smtpClient = new SmtpClient();
                    smtpClient.Host = "smtp.exmail.qq.com";
                    //smtpClient.Host = "smtp.163.com"; 
                    //smtpClient.Host = "smtp.exmail.sina.com"; 
                    smtpClient.Port = 25;
                    smtpClient.EnableSsl = true;
                    smtpClient.UseDefaultCredentials = false;
                   
                    smtpClient.Credentials = new System.Net.NetworkCredential("       ", "    ");
                 
                    smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
                    smtpClient.Send(mailMessage);
                    result = "1";
                }
                catch(Exception ex)
                {
                    result = "-1";
                }
                return result;
            }