User.Identity.IsAuthenticated equivalent in asp.net core
<p>I am using the default MVC 6 template in Visual Studio. I need to check if a user is authenticated in a class. This should be very simple but I cannot figure out why its not working.
Thanks in advance.</p>

<pre><code>using Microsoft.AspNet.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Security.Claims;
using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.EntityFramework;
using System.Security.Principal;

namespace fake.Classes
{
    public class fakeUser
    {
        public static string getBrand()
        {
            if (User.Identity.IsAuthenticated)
            {
                return getThemeName();
            }
        }
    }
}
</code></pre>