Async method not executing from within razor component - asp.net-core

Question

I have a server-side Blazor app, and in 'app.razor' I have:
<CascadingAuthenticationState>
<Router AppAssembly="#typeof(Program).Assembly" PreferExactMatches="#true">
<Found Context="routeData">
<AuthorizeRouteView RouteData="#routeData" DefaultLayout="#typeof(MainLayout)">
<NotAuthorized>
#(myService.Login())
</NotAuthorized>
<Authorizing>
<p>Bitte warten...</p>
</Authorizing>
</AuthorizeRouteView>
</Found>
<NotFound>
<LayoutView Layout="#typeof(MainLayout)">
<p>Sorry, there's nothing at this address.</p>
</LayoutView>
</NotFound>
</Router>
</CascadingAuthenticationState>
This is my service:
public class MyService : IMyService
{
protected readonly HttpClient httpClient;
public MyService(
HttpClient httpClient)
{
this.httpClient = httpClient;
}
public async Task Login()
{
await httpClient.GetAsync(loginUrl);
}
}
And the service is registered as follows:
services.AddHttpClient<IMyService, MyService>(client =>
{
client.BaseAddress = new Uri(someUrl);
});
However, I get the following error on running:
System.Runtime.CompilerServices.AsyncTaskMethodBuilder1+AsyncStateMachineBox1[System.Threading.Tasks.VoidTaskResult,App.Services.MyService+d__5]
What am I doing wrong?

Answer 1

Lots...
This is how NotAuthorized should look like:
<NotAuthorized>
#if (!context.User.Identity.IsAuthenticated)
{
<RedirectToLogin />
}
else
{
<p>You are not authorized to access this resource.</p>
}
</NotAuthorized>
In the if clause you check if the user is authenticated. If not you redirect him to the RedirectToLogin component. You do not call a service method here.
In the else clause you display a message... This is done because a user can be authenticated, but he's still not authorized to access a resource.
RedirectToLogin.razor
#inject myService myService
Put here html elements to gather the users' credentials with a "Login"
button, which when clicked, calls myService.Login() method to autenticate the
user.
#code
{
// Note: this code sample demonstrate how to login a user when you use
// Asp.Net Core Identity. It is not clear what identity system are you using
protected override void OnInitialized()
{
ReturnUrl = "~/" + ReturnUrl;
NavigationManager.NavigateTo($"Identity/Account/Login?returnUrl=
{ReturnUrl}", forceLoad:true);
}
}
Note: This expression: #(myService.Login()) is evaluated to System.Threading.Tasks.VoidTaskResult which causes the error. You should use return await httpClient.GetAsync(loginUrl); instead