MailMessage Msg = new MailMessage();
            Msg.From = new MailAddress("geral@seusite.com");
            Msg.To.Add("geral@seusite.com");
            StreamReader reader = new StreamReader(Server.MapPath("modeloemailcompra.html"));
            string readFile = reader.ReadToEnd();
            string StrContent = "";
            StrContent = readFile;
          
            Msg.Subject = "Cheirabem - ca vai um teste";
            Msg.Body = StrContent.ToString();
            Msg.IsBodyHtml = true;
            // your remote SMTP server IP.
            SmtpClient smtp = new SmtpClient("mail.seusite.com");
            smtp.Credentials = new NetworkCredential("site", "passe");
            smtp.Send(Msg);