C#发送邮件

 protected void Page_Load(object sender, EventArgs e)
    {
        string sendTo = "wei.dehao@covics.com";
        System.Net.Mail.SmtpClient client = new SmtpClient();
        //STMP服务器
        client.Host = "smtp.163.com";
        client.UseDefaultCredentials = false;
        //                                                                                     发送人的邮箱用户名和密码
        client.Credentials = new System.Net.NetworkCredential("gd_honsen", "honsen");
        client.DeliveryMethod = SmtpDeliveryMethod.Network;

        //发送人的邮箱地址，接收人的邮箱地址
        System.Net.Mail.MailMessage message = new MailMessage("gd_honsen@163.com", sendTo);
        message.Subject = "系统问题反馈";
        message.Body = string.Format("共有n个人访问");
        message.BodyEncoding = System.Text.Encoding.UTF8;
        message.IsBodyHtml = true;
        //添加附件  
        Attachment data = new Attachment(@"e:\11.txt", System.Net.Mime.MediaTypeNames.Application.Octet);
        message.Attachments.Add(data);
        try
        {
            client.Send(message);
        }
        catch (Exception ex)
        {
        }
    }

补充附件

  string DocmentPath = Server.MapPath("Log/log"+DateTime.Now.Hour+DateTime.Now.Minute+DateTime.Now.Second+".txt");
        string memo = "日志内容";
        System.Text.Encoding enc = System.Text.Encoding.GetEncoding("gb2312");
        StreamWriter sw = new StreamWriter(DocmentPath, false, enc);
        sw.WriteLine(memo);
        sw.Close();

        string sendTo = "wei.dehao@covics.com";
        System.Net.Mail.SmtpClient client = new SmtpClient();
        //STMP服务器
        client.Host = "smtp.163.com";
        client.UseDefaultCredentials = false;
        //                                                                                     发送人的邮箱用户名和密码
        client.Credentials = new System.Net.NetworkCredential("gd_honsen", "honsen");
        client.DeliveryMethod = SmtpDeliveryMethod.Network;

        //发送人的邮箱地址，接收人的邮箱地址
        System.Net.Mail.MailMessage message = new MailMessage("gd_honsen@163.com", sendTo);
        message.Subject = "系统问题反馈";
        message.Body = string.Format("共有n个人访问");
        message.BodyEncoding = System.Text.Encoding.UTF8;
        message.IsBodyHtml = true;
        //添加附件  
        Attachment data = new Attachment(Server.MapPath("Log/log1.txt"), System.Net.Mime.MediaTypeNames.Application.Octet);
        message.Attachments.Add(data);
        try
        {
            client.Send(message);
        }
        catch (Exception ex)
        {
        }