c# winform 邮件发送 .net邮件发送

public void SendMailUseYeah()
        {

            System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();

            msg.To.Add("收件地址");
            //msg.To.Add("");
            //msg.To.Add("[e-mail]");
            /*
             * msg.To.Add("[e-mail]");
             * msg.To.Add("[e-mail]");
             * msg.To.Add("[e-mail]");可以发送给多人
             */
            msg.CC.Add("抄送地址");
            /*
             * msg.CC.Add("[e-mail]");
             * msg.CC.Add("[e-mail]");可以抄送给多人
             */
            msg.From = new MailAddress("发件人地址", "发件人姓名",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dddddd";//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("mail地址", "password");
            //上述写你的yeah邮箱和密码
            client.Port = 25;//yeah使用的端口
            client.Host = "smtp.yeah.net";
            client.EnableSsl = false;//经过ssl加密
            object userState = msg;
            try
            {
                client.SendAsync(msg, userState);
                //简单一点儿可以client.Send(msg);
                MessageBox.Show("发送成功");
            }
            catch (System.Net.Mail.SmtpException ex)
            {
                MessageBox.Show(ex.Message, "发送邮件出错");
            }
        }