layout.cshtml

@using asp.net_core_boilerplte.Utils;

<ul class="navbar-nav">
    @if (User?.Identity?.IsAuthenticated == true)
    {
        <li class="nav-item">
            <a class="nav-link text-dark" title="Manage">Hello @UserUtils.GetDisplayName(User)!</a>
        </li>
        <li class="nav-item">
            <a class="nav-link text-dark" asp-area="" asp-controller="Identity" asp-action="Logout">Logout</a>
        </li>
    }
    else
    {
        <li class="nav-item">
            <a class="nav-link text-dark" asp-controller="Identity" asp-action="Login">Login</a>
        </li>
    }
</ul>