public ActionResult Login(LoginModel model, string returnUrl)
        {
            Session["Name"] = model.UserName;
            if (ModelState.IsValid && WebSecurity.Login(model.UserName, model.Password, persistCookie: model.RememberMe))
            {
                return RedirectToLocal(returnUrl);
            }

            // If we got this far, something failed, redisplay form
            ModelState.AddModelError("", "The user name or password provided is incorrect.");
            return View(model);
        }
        public ActionResult Login(LoginModel model)
        {
            if (ModelState.IsValid)
            {
                var dao = new UserDao();
                var result = dao.Login(model.UserName, Encryptor.MD5Hash(model.Password));
                if (result == 1)
                {
                    var user = dao.GetById(model.UserName);
                    var userSession = new UserLogin();
                    userSession.UserName = user.Username;
                    userSession.UserID = user.ID;

                    Session.Add(CommonConstants.USER_SESSION, userSession);
                    return Redirect("/");
                }
                else if (result == 0)
                {
                    ModelState.AddModelError("", "Tài khoản không tồn tại");
                }
                else if (result == -1)
                {
                    ModelState.AddModelError("", "Tài khoản đã bị khóa");
                }
                else if (result == -2)
                {
                    ModelState.AddModelError("", "Mật khẩu không đúng");
                }
            }

            else
            {

            }
            return View(model);
        }