asp.net 发送邮件

web.config:
    <system.net>
        <mailSettings>
            <smtp deliveryMethod="Network" from="chunyou128&lt;you@163.com&gt;">
                <network host="smtp.163.com" />
            </smtp>
        </mailSettings>
    </system.net>
C#       
 try
        {
            MailAddress from = new MailAddress("mymail@163.com");
            MailAddress to = new MailAddress("mymail@163.com");
            MailMessage message = new MailMessage(from, to);
            message.Subject = "Test Message";//发送邮件的标题
            message.Body = "yuanyouchun";//发送邮件的内容
            //if (FileUpload1.PostedFile.FileName != "")
            //{//发送附件
            // Attachment att = new Attachment(FileUpload1.PostedFile.FileName);
            // message.Attachments.Add(att);
            //}
            SmtpClient client = new SmtpClient("smtp.163.com");
            client.UseDefaultCredentials