Session variable in view

Question

Some time ago I created some simply login with session. It was a MVC app but with .net framework 4.6 if I'm correct. And I could there use something like

<h2>@Session["ID"]</h2>

And ID from session variable should be in h2 tag. But now I try to build same but with .net core 2.0.

My startup.cs:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddDbContext<L2Context>(options =>
            options.UseSqlite("Data Source=test.db"));

    services.AddDistributedMemoryCache(); // Adds a default in-memory implementation of IDistributedCache
    services.AddSession(options => {
        options.IdleTimeout = TimeSpan.FromMinutes(30);
    });
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
    }

    app.UseStaticFiles();
    app.UseSession();

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });
}

Controller to save data into session:

[HttpPost]
public IActionResult Login(Users user)
{
    var optionsBuilder = new DbContextOptionsBuilder<L2Context>();
    optionsBuilder.UseSqlite("Data Source=test.db");

    using (L2Context db = new L2Context(optionsBuilder.Options))
    {
        var user = db.Users.Single(u => u.Login == user.Login && u.Password == user.Password);
        if (user != null)
        {
            HttpContext.Session.SetString("ID", user.ID.ToString());
            HttpContext.Session.SetString("Login", user.Login.ToString());
            return RedirectToAction(nameof(LoggedIn));
        }
        else
        {
            ModelState.AddModelError("", "Login or password is invalid");
        }
    }
    return View();
}

LoggedIn View:

@{
    ViewData["Title"] = "LoggedIn";
}

<h4> Hello @Session["Login"]</h4>

So, do I have some error here? I tough it was working last time when I used it.

I get:

error CS0103: The name 'Session' does not exist in the current context

Answer 1

In ASP.NET Core, the View doesn't have access to the Session property of the HttpContext object by default. You can access it by importing the Http Namespace within the view:

//import the namespace to make the class available within the view
@using Microsoft.AspNetCore.Http

You can then access the Session property of the HttpContext object:

<h4> Hello @HttpContext.Session.GetString("Login")</h4>