为什么要注册第二个用户时，MVC简单会员身份令牌返回null？

Question

I dont know what the wrong is but I cant take membership the token for the second user. I can easily register the first user but when i wanted to register second user, token comes null. I can get the user to the controller also WebSecurity.CreateUserAndAccount method gets values from the user. it is created in User Table of the database but not in dbo.webpages_Membership Table. I have deleted the database and migrated twice. Eachtime I registered the first user without problem. But had problem when registering another user.

Please see my codes;

My Register View;

  @using (Html.BeginForm("Register", "Admin", FormMethod.Post))
                {
                    @Html.AntiForgeryToken()
                    @Html.ValidationSummary(true)
                    <form action="#">
                        <input type="text" name="Name" placeholder="Ad" />
                        <input type="email" name="Email" placeholder="E-posta Adresi" />
                        <input type="password" id="PasswordId" name="Password" placeholder="Şifre" />
                        <input type="password" id="PasswordConfirmId" name="PasswordConfirm" placeholder="Şifreni Onayla" /><label id="mismatch" style="visibility:hidden">Şifre uyuşmuyor</label>
                        <button type="submit" class="btn btn-default">Hesap Oluştur</button>
                    </form>
                }

My Controller;

    public ActionResult Register()
    {
        return View();
    }  

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Register(User user)
    {
        if (ModelState.IsValid)
        {
            try
            {
                string token = WebSecurity.CreateUserAndAccount(user.Email, user.Password, new { user.Password, user.PasswordConfirm, user.Email, user.Name }, true);

                int userId = db.Users.FirstOrDefault(u => u.Email == user.Email).Id;
                SendMail(user.Email, user.Password, user.Name, userId, token);
                if (!Roles.RoleExists("User"))
                    Roles.CreateRole("User");
                Roles.AddUserToRole(user.Email, "User");

                return RedirectToAction("Index", "Home");
            }
            catch (MembershipCreateUserException ex)
            {
                ViewBag.Error = ex.Message;
                return View(user);
            }
        }
        return View(user);
    }

Answer 1

I figured out that the problem is SQL Collation problem. CreateUserAndAccount Method try to upper the email "gmail" to "GMAİL". As there is no such a character in english, it returns error.

I have solved the problem adding one line code just before try statement and changed user.Email parameters with UpperEmail.

string UpperEmail = user.Email.ToUpper().ToString();