[Solved] ASP.Net MVC Error: System.Web.SessionState.HttpSessionState.this[string].get values returning null

Hello there,

I am running an ASP MVC site locally (.Net 4.7) and am experiencing an issue when trying to retrieve a value from session.

I am calling the code from a 

        private ActionResult countries()
        {
            string[] tcode = System.Web.HttpContext.Current.Session["tCode"].ToString().Split(',');  //LINE OF ERROR

            var personModel = new PersonModel
            {
                Countries = PopulateDropDown(" SELECT * FROM `dotable` WHERE `tCode` IN ('" + string.Join("','", tcode) + "') " +
                                             " GROUP BY `tCode` ORDER BY `tCode` ASC;", "tCode", "tCode")
            };

            return View(personModel);
        }

But on return I have this error

Object reference not set to an instance of an object.
System.Web.SessionState.HttpSessionState.this[string].get values returning null

On this line

string[] tcode = System.Web.HttpContext.Current.Session["tCode"].ToString().Split(',');  //LINE OF ERROR

Please can you help me ?

controller.cs

        [HttpGet]
        public ActionResult Index()
        {
            sessionuser();
            recognize();

            if (Convert.ToInt32(System.Web.HttpContext.Current.Session["UserLiv"]) > 0)
                return RedirectToAction("About");

            return countries();
        }

        private ActionResult countries()
        {
            string[] tcode = System.Web.HttpContext.Current.Session["tCode"].ToString().Split(',');  //LINE OF ERROR

            var personModel = new PersonModel
            {
                Countries = PopulateDropDown(" SELECT * FROM `dotable` WHERE `tCode` IN ('" + string.Join("','", tcode) + "') " +
                                             " GROUP BY `tCode` ORDER BY `tCode` ASC;", "tCode", "tCode")
            };

            return View(personModel);
        }

        private void sessionuser()
        {
            if (!String.IsNullOrEmpty(HttpContext.User.Identity.Name.ToString()))
            {
                System.Web.HttpContext.Current.Session["tUser"] = HttpContext.User.Identity.Name.ToString();
            }

            System.Web.HttpContext.Current.Session.Timeout = 28800;
        }

        private void recognize()
        {
            try
            {
                string cs = ConfigurationManager.ConnectionStrings["cnj"].ConnectionString;

                using (var connection =
                    new MySqlConnection(cs))
                {
                    string commandText = "SELECT `tUser`,`tCode` FROM `tUser` WHERE `tUser`=@Username;";

                    using (var command =
                        new MySqlCommand(commandText, connection))
                    {
                        if (!String.IsNullOrEmpty(HttpContext.User.Identity.Name.ToString()))
                        {
                            command.Parameters.AddWithValue("@Username", HttpContext.User.Identity.Name.ToString());
                        }

                        connection.Open();

                        string tUser = string.Empty;
                        string UO_AUI = string.Empty;

                        using (MySqlDataReader reader =
                            command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                tUser = reader["tUser"].ToString();

                                if (string.IsNullOrEmpty(tCode))
                                {
                                    tCode = reader["tCode"].ToString();
                                }
                                else
                                {
                                    if (reader["tCode"] != DBNull.Value)
                                    {
                                        tCode = tCode + "," + reader["tCode"].ToString();
                                    }
                                }

                                System.Web.HttpContext.Current.Session["tUser"] = tUser.ToString();
                                System.Web.HttpContext.Current.Session["tCode"] = tCode.ToString();
                                System.Web.HttpContext.Current.Session.Timeout = 28800;

                                if (String.IsNullOrEmpty(tUser))
                                {
                                    ViewBag.Message = String.Format("No user!");
                                }
                            }
                        }
                    }
                    connection.Close();
                }
            }
            catch (Exception ex)
            {
                TempData["Message"] = "Login failed.Error - " + ex.Message;
            }
        }

        [HttpPost]
        public ActionResult Index(PersonModel person)
        {
            string[] tcode = System.Web.HttpContext.Current.Session["tcode"].ToString().Split(',');

            person.Countries = PopulateDropDown(" SELECT * FROM `dotable` WHERE `tCode` IN ('" + string.Join("','", tcode) + "') " +
                                                " GROUP BY `tCode` ORDER BY `tCode` ASC;", "tCode", "tCode")

            if (ModelState.IsValid)
            {
                return View(person);
            }

            return View(person);
        }