I am working on my school project, which I have done. And want to try to add something more. Right now I have the problem with role-based authorzation. I have set up in the controllers to autherize only the one that should be able to get in. However I want to have in _Layout so if you are logged in and has the role "Admin" You would be able to see a link to the Admin page. And if you are a normal user, you can't.

Here is some of my code, I can provide a lot more if need be. Thanks for your time

_Layout Page:

                        @if (User.IsInRole("Admin"))
                    {
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-page="RoleTest/Admin">Admin Page</a>
                        </li>
                    }
                    @if (User.IsInRole("Admin") || User.IsInRole("NormalPW"))
                    {
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-page="RoleTest/UserWithPower">UserWithPowerPage</a>
                        </li>
                    }
                    @if (User.IsInRole("Admin") || User.IsInRole("NormalPW") || User.IsInRole("NormalNoPW"))
                    {
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-page="RoleTest/UserWithPower">UserWithoutPowerPage</a>
                        </li>
                    }

I have tried this too:

                    @if (LoginModel.LoggedInUser.UserRole == "Admin")
                    {
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-page="RoleTest/Admin">Admin Page</a>
                        </li>
                    }

But I get a "Possible 'System.NullReferenceException'.

This is my Login controller:

       public async Task<IActionResult> OnPost()
    {
        List<User> users = _userService.GetAll();
        
        foreach (User u in users)
        {
            if (UserName == u.UserName && Password == u.Password)
            {
               
                LoggedInUser = u;
                
                var claims = new List<Claim>
                {
                    new Claim(ClaimTypes.Name, UserName), 
                    

                };
                var claimsIdentity = new ClaimsIdentity(claims,
                    CookieAuthenticationDefaults.AuthenticationScheme);
                
                await HttpContext.SignInAsync(
                    CookieAuthenticationDefaults.AuthenticationScheme,
                    new ClaimsPrincipal(claimsIdentity));
                return RedirectToPage("/UserStories/Index");
            }
        }

        Message = "Invalid attempt";
        return Page();
    }