ASP.NET MVC: Get user id of currently logged in user

Question

I am new to ASP.NET MVC and am trying to create a web app.

The problem I have is that in the controller class I need to get the UserID of the current user, but I am very confused about how one would do that. Also, it seems that the user is not authenticated after logging in, because if I use the [Authorize] annotation it throws an HTTP Error 401.0 - Unauthorized error.

This is my Authentication.cs class:

public static class Authentication
{
    public static bool CreateNewTicket(User user, bool rememberMe)
    {

        try
        {
            FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(
                1,
                user.Email,
                DateTime.Now,
                DateTime.Now.AddDays(5),
                rememberMe,
                user.ID.ToString(),
                FormsAuthentication.FormsCookiePath
                );

            string encryptedTicket = FormsAuthentication.Encrypt(ticket);

            HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);
            cookie.HttpOnly = true;
            if (!HttpContext.Current.Request.IsLocal)
                cookie.Secure = true;

            HttpContext.Current.Response.Cookies.Add(cookie);

            return true;
        }
        catch
        {
            return false;
        }
    }
    public static bool AuthUser(string Email, string Password)
    {
        using (var db = new AntContext())
        {
            string password = Password;
            string email = Email;

            string hashedPW = GetHash(password);

            bool userValid = db.Users.Any(user => user.Email == email && user.Password == hashedPW);

            if (userValid)
            {
                var actUser = db.Users.FirstOrDefault(u => u.Email == Email && u.Password == hashedPW);

                if (!actUser.IsLocked)
                {
                    if (CreateNewTicket(actUser, false))
                    {

                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                else if (actUser.IsLocked)
                {



                }
            }
            return false;

        }
    }

The actual problem happens when I try to store data in a database.

[HttpPost]
    public ActionResult Q_FirstPage(ViewModels.Q1_Answer_VM vm)
    {
        vm.Qst = new Models.Questionnaire();
        vm.Qst.NumericAnswers = new List<Models.NumericAnswer>();
        vm.Qst.TextAnswers = new List<Models.TextAnswer>();
        vm.Qst.IsComplete = false;
        vm.Qst.StartedOn = DateTime.Now;
        vm.Qst.NumericAnswers.Add(vm.Breite);
        vm.Qst.NumericAnswers.Add(vm.Tiefe);
        vm.Qst.NumericAnswers.Add(vm.Hoehe);
        vm.Qst.TextAnswers.Add(vm.Sonstiges);

        //vm.qst.User_ID = 22; if I set the User ID manually, it works

        db.Questionnaires.Add(vm.Qst);
        db.SaveChanges();

        return View();
    }

The Viewmodel works fine and returns the data input, but the UserID is null. The data table "Questionnaire" uses the UserID as a foreign key, which makes it throw an error when it comes to the savedata() part because I guess it expects the correct UserID. So I guess I need to get the current UserID, pass it to the instantiated object which is then passed to the data context and then saved into the database.

Unfortunately, I find it very hard to find complete information about how user authentication works in ASP.NET.

If you need more information, please let me know.

This is my Login method:

 [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Login(Login_VM login_vm)
    {
        if (!ModelState.IsValid)
        {
            return View(login_vm);
        }

        if (Authentication.AuthUser(login_vm.Email, login_vm.Password) == true && (login_vm.Email != null || login_vm.Password != null))
        {

            Classes.Authentication.CreateNewTicket(login_vm.usr, true);
            return RedirectToAction("Login");
        }

        else
            return View("~/Views/Home/Index.cshtml");
    }

And this is my registration method:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult AddUser(User model)
// add new User to db
{

    if (ModelState.IsValid)
    {
        User usr = new Models.User();
        usr = model;
        model.Password = Authentication.GetHash(model.Password);
        db.Users.Add(model);
        db.SaveChanges();
    }
    return View();
}

Solution

Solved the problem by following this link: howto get the user id from a FormsAuthentication page in asp.net MVC? posted by https://stackoverflow.com/users/2516718/derloopkat

The System.Web.HttpContext.Current.User.Identity.Name Function returns the "name" attribute in the Authentication Ticket, which in my case was the email address. I then got the User ID by having a query to the Users database.

db.Users.Where(x => x.Email == System.Web.HttpContext.Current.User.Identity.Name).FirstOrDefault().ID;

Thanks for everybody's help.

---

Update in 2020: The query can be simplified to:

db.Users.FirstOrDefault(x => x.Email == System.Web.HttpContext.Current.User.Identity.Name).ID;