Login flow with Intrnet check

Question

I have my shell

 <ShellContent
        ContentTemplate="{DataTemplate pages:StartupPage}"
        Shell.FlyoutBehavior="Disabled"
        Route="StartupPage"
        Shell.FlyoutItemIsVisible="False" />
    <ShellContent
        ContentTemplate="{DataTemplate pages:LoginPage}"
        Shell.FlyoutBehavior="Disabled"
        Route="LoginPage"
        Shell.FlyoutItemIsVisible="False" />
    <ShellContent
        ContentTemplate="{DataTemplate pages:NoInternetPage}"
        Shell.FlyoutBehavior="Disabled"
        Route="NoInternetPage"
        Shell.FlyoutItemIsVisible="False" />
    <FlyoutItem
        FlyoutDisplayOptions="AsMultipleItems"
        Route="WelcomePage">
        <ShellContent
            Title="Welcome"
            ContentTemplate="{DataTemplate pages:WelcomePage}" />
        <ShellContent
            Title="Join meeting"
            ContentTemplate="{DataTemplate pages:JoinMeetingPage}" />
        <ShellContent
            Title="Manage Course"
            ContentTemplate="{DataTemplate pages:ManageCoursePage}" />
        <ShellContent
            Title="New Lecture"
            ContentTemplate="{DataTemplate pages:NewLecturePage}" />
        <ShellContent
            Title="New Test"
            ContentTemplate="{DataTemplate pages:NewTestPage}" />
        <ShellContent
            Title="Schedule lecture"
            ContentTemplate="{DataTemplate pages:ScheduleLecturePage}" />
        <ShellContent
            Title="Schedule test"
            ContentTemplate="{DataTemplate pages:ScheduleTestPage}" />
        <ShellContent
            Title="Assigned courses"
            ContentTemplate="{DataTemplate pages:NotificationsPage}" />
    </FlyoutItem>
</Shell>

the first page, is the startupPage

    private readonly StartupPageViewModel startupPageViewModel;
    public StartupPage(StartupPageViewModel startupPageViewModel) {
        InitializeComponent();
        this.startupPageViewModel = startupPageViewModel;
        BindingContext = startupPageViewModel;
    }
    protected override async void OnAppearing() {
        base.OnAppearing();
        await startupPageViewModel.CheckInternet();
    }
}

I also have the vm

public class StartupPageViewModel(IAppService appService, IConnectivity connectivity) : BaseViewModel {
    public async Task CheckInternet() {
        if(connectivity.NetworkAccess is not NetworkAccess.Internet) {
            await appService.NavigateTo($"//{nameof(NoInternetPage)}");
        } else {
            await appService.NavigateTo($"//{nameof(LoginPage)}");
        }
    }
}

and the app

    public App(AppShell shell) {
        InitializeComponent();
        Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense(Constants.LICENSE);
        MainPage = shell;
    }
}

but I get the error

Pending Navigations still processing

Answer 1

Hello,

Pending Navigations still processing

This is a known issue with shell navigation, and based on the discussion in Pending Navigations still processing exception when navigating to the page #17608, there are multiple ways you can work around it.

Workaround 1:

If I add await Task.Delay(1) it will work.

Workaround 2:

I had the same issue only on windows, I felt the Task.Delay(1) workaround a bit cheap and dirty so came up with this code:

if (DeviceInfo.Platform == DevicePlatform.WinUI)
{
    AppShell.Current.Dispatcher.Dispatch(async () =>
    {
        await Shell.Current.GoToAsync($"//{nameof(DashboardPage)}");
    });
}
else
{
    await Shell.Current.GoToAsync($"//{nameof(DashboardPage)}");
}

Best Regards,

Alec Liu.

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