[HttpPost]
    public async Task<ActionResult> Index2(LigneCommandeT LigneCommandeT , string submit)
    {
        switch (submit)
        {
            case "Ajouter" :
        context.LigneCde.Add(LigneCommandeT);
        context.SaveChanges();
        return RedirectToAction("Index2");
             break;
            case  "Valider" :
            // var message = EMailTemplate("Welcome");
            await  MessageServices.SendEmailAsync("sabrinenaceur25@gmail.com", "Welcome!",  "message");

             return RedirectToAction("Index3");
            break;
            default :
            return RedirectToAction("Index2");
            break;
        }
    }

public async static Task SendEmailAsync(string email , string subject ,string message)
    {
        try
        {
            var _email="sabrinenaceur25@gmail.com"; // sender's email
            var _epass = ConfigurationManager.AppSettings["EmailPassword"]; // get our password from web.config
            var _dispName = "Sabrine";
            MailMessage  MyMessage = new MailMessage();
            MyMessage.To.Add(email);
            MyMessage.From = new  MailAddress(_email,_dispName);
            MyMessage.Subject = subject ;
            MyMessage.Body = message ;
            MyMessage.IsBodyHtml = true;

            using(SmtpClient smtp = new SmtpClient())
            {
                smtp.EnableSsl =true ;
                smtp.Host = "smtp.live.com";
                smtp.Port = 587 ;
                smtp.UseDefaultCredentials = false ;
                smtp.Credentials = new NetworkCredential(_email,_epass);
                smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
                smtp.SendCompleted   += (s,e) => {smtp.Dispose();} ;
                await smtp.SendMailAsync(MyMessage);


            }
        }
        catch(Exception ex)
        {
            throw ex ;
        }

<appSettings>
<add key="webpages:Version" value="3.0.0.0" />
<add key="webpages:Enabled" value="false" />
<add key="ClientValidationEnabled" value="true" />
<add key="UnobtrusiveJavaScriptEnabled" value="true" />
<add key="EmailPassword" value=""  />
   </appSettings>

<system.net>
  <mailSettings>
     <smtp deliveryMethod="Network">
       <network enableSsl="true" host="smtp.live.com" port="587" defaultCredentials="false" userName="sabrinenaceur25@gmail.com" password=""/>
     </smtp>
  </mailSettings>