Identity example done for blog https:gavilan.blog

Identity_Example.cs

using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using IdentityDemo.Models;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Authorization;

namespace IdentityDemo.Controllers
{
    public class HomeController : Controller
    {
        private readonly UserManager<ApplicationUser> userManager;
        private readonly RoleManager<IdentityRole> roleManager;

        public HomeController(UserManager<ApplicationUser> userManager,
            RoleManager<IdentityRole> roleManager
            )
        {
            this.userManager = userManager;
            this.roleManager = roleManager;
        }

        public IActionResult Index()
        {
            if (User.Identity.IsAuthenticated)
            {
                // get user's claims
                var claims = User.Claims.ToList();

            }

            return View();
        }

        public async Task<IActionResult> About()
        {
            // Add user to the role
            if (User.Identity.IsAuthenticated)
            {
              
                //   await roleManager.CreateAsync(new IdentityRole("Admin")); // Creates the role
                var user = await userManager.GetUserAsync(HttpContext.User);
                await userManager.AddToRoleAsync(user, "Admin");
            }

            ViewData["Message"] = "Your application description page.";

            return View();
        }

        [Authorize(Roles = "Admin")]
        public IActionResult Contact()
        {
            ViewData["Message"] = "Your contact page.";

            return View();
        }

        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
    }
}