C#发送邮件（使用SSL,587端口）

static readonly string smtpServer = System.Configuration.ConfigurationManager.AppSettings["SmtpServer"];
        static readonly string userName = System.Configuration.ConfigurationManager.AppSettings["UserName"];
        static readonly string pwd = System.Configuration.ConfigurationManager.AppSettings["Pwd"];
        static readonly int smtpPort = Convert.ToInt32(System.Configuration.ConfigurationManager.AppSettings["SmtpPort"]);
        static readonly string authorName = System.Configuration.ConfigurationManager.AppSettings["AuthorName"];
        protected void Page_Load(object sender, EventArgs e)
        {
            MailMessage msg = new System.Net.Mail.MailMessage();
            msg.To.Add("1833793557@qq.com");

            msg.From = new MailAddress(userName, authorName, System.Text.Encoding.UTF8);
            /* 上面3个参数分别是发件人地址（可以随便写），发件人姓名，编码*/
            msg.Subject = "这是测试邮件";//邮件标题    
            msg.SubjectEncoding = System.Text.Encoding.UTF8;//邮件标题编码    
            msg.Body = "邮件内容";//邮件内容    
            msg.BodyEncoding = System.Text.Encoding.UTF8;//邮件内容编码    
            msg.IsBodyHtml = false;//是否是HTML邮件    
            msg.Priority = MailPriority.High;//邮件优先级    

            SmtpClient client = new SmtpClient();
            client.Credentials = new System.Net.NetworkCredential(userName, pwd);
            
            client.Port = 587; 
            client.Host = smtpServer;
            client.EnableSsl = true; //经过ssl加密    
            object userState = msg;

            //异步发送
            client.SendAsync(msg, userState);            
            //同步发送
            //client.Send(msg);
        }