Seekers/AppShell.xaml.cs

using Justice.Helpers;

namespace Justice
{
    public partial class AppShell : Shell
    {
        public Command LogoutCommand { get; }
        public AppShell()
        {
            InitializeComponent();

            Routing.RegisterRoute("LoginPage", typeof(Views.LoginPage));
            Routing.RegisterRoute("DashboardPage", typeof(Views.DashboardPage));
            Routing.RegisterRoute("ViewReportsPage", typeof(Views.ViewReportsPage));
            
            LogoutCommand = new Command(async () =>
            {
                AuthHelper.Logout();
                await Shell.Current.GoToAsync("//LoginPage");
            });

            BindingContext = this;


        }

        protected override async void OnNavigating(ShellNavigatingEventArgs args)
        {
            base.OnNavigating(args);

            // Check if user is authenticated 
            if (!AuthHelper.IsLoggedIn && args.Target.Location.OriginalString.Contains("ViewReportsPage") || !AuthHelper.IsLoggedIn && args.Target.Location.OriginalString.Contains("DashboardPage"))
            {
                args.Cancel(); // Prevent navigation
                await Shell.Current.GoToAsync("//LoginPage");
            }
        }
    }
}