User.Identity.GetUserId（）在cotrollers构造函数中返回null

Question

User.Identity.GetUserId() returns null in controller contructor this is my form :

@using (Html.BeginForm("Login", "Account", new { ReturnUrl = ViewBag.ReturnUrl }, FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
    @Html.ValidationSummary("", new { @class = "text-danger" })
    @Html.AntiForgeryToken()

    @Html.TextBoxFor(m => m.Email, new { @class = "form-control", placeholder = "Email" })         
    @Html.PasswordFor(m => m.Password, new { @class = "form-control", placeholder = "Mot de passe" })

    <input type="submit" id="ModalSubmitButton" class="btn btn-primary btn-lg btn-block login-button" value="Se connecter" />
}

Then in the login action in account Controller:

[HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
        {
    var result = await SignInManager.PasswordSignInAsync(model.Email, model.Password, model.RememberMe, shouldLockout: false);
                switch (result)
                {
                    case SignInStatus.Success:
                        //return RedirectToLocal(returnUrl);
                        return RedirectToAction("Index", "User");
                    case SignInStatus.LockedOut:
                        return View("Lockout");
                    case SignInStatus.RequiresVerification:
                        return RedirectToAction("SendCode", new { ReturnUrl = returnUrl, RememberMe = model.RememberMe });
                    case SignInStatus.Failure:
                    default:
                        ModelState.AddModelError("", "Tentative de connexion non valide.");
                        return PartialView("_SignIn",model);
                }

And in the userController constructor i have :

public ActionResult Index()
        {
            var x = User.Identity.GetUserId();
            return View();
        }

when i redirect to HomeController i can get the userID but when i redirect to UserController the userId = null

Update : i'm using Int as ID instead of string

Answer 1

Retrieve current logged in user UserID

using Microsoft.AspNet.Identity;

In controller constructor use this:

System.Web.HttpContext.Current.User.Identity.GetUserId();

Instead of this is used in controller Action Method:

var userId = User.getUserId();

Because in constructor you can't get the current User.Identity by default you need to specify it explicitly.