App.razor

@using Chaos.Models.DbModels
@using Microsoft.AspNetCore.Identity
@using System.Security.Claims
@using Chaos.Shared

@inject AuthenticationStateProvider authenticationStateProvider
@inject SignInManager<GameUser> signInManager
@inject UserManager<GameUser> userManager

<CascadingAuthenticationState>
    <CascadingValue Value="@loggedUserId" Name="LoggedUserId">
        <CascadingValue Value="@username" Name="Username">
            <Router AppAssembly="@typeof(App).Assembly">
                <Found Context="routeData">
                    <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)">
                        <NotAuthorized>
                            <NotAuthorizedPage />
                        </NotAuthorized>
                        <Authorizing>
                            <h1>Authorization in progress...</h1>
                        </Authorizing>
                    </AuthorizeRouteView>
                </Found>
                <NotFound>
                    <NotFoundPage />
                </NotFound>
            </Router>
        </CascadingValue>
    </CascadingValue>
</CascadingAuthenticationState>

@code
{
    string loggedUserId = "";
    string username = "";

    protected override async Task OnInitializedAsync()
    {
        var authState = await authenticationStateProvider.GetAuthenticationStateAsync();

        if (signInManager.IsSignedIn(authState.User))
        {
            loggedUserId = authState.User.Claims.Where(u => u.Type == ClaimTypes.NameIdentifier).FirstOrDefault()?.Value;
            username = (await userManager.FindByIdAsync(loggedUserId)).UserName;
        }
    }
}