Splash Screen?

[renrutsirhc]

Hi all,

I'm trying to implement a splashscreen in my app as there's a fair bit of time pulling data from a database on startup. This isn't super well documented and the two github issues I could find are from before the Application Lifetime code was changed. #2674 #4155

Here's my Program.cs

class Program
    {
        // Initialization code. Don't use any Avalonia, third-party APIs or any
        // SynchronizationContext-reliant code before AppMain is called: things aren't initialized
        // yet and stuff might break.

        [STAThread]
        public static void Main(string[] args)
        {
            BuildAvaloniaApp()
              .Start(AppMain, args);
        }

        // Avalonia configuration, don't remove; also used by visual designer.
        public static AppBuilder BuildAvaloniaApp()
            => AppBuilder.Configure<App>()
                .UsePlatformDetect()
                .LogToTrace()
                .UseReactiveUI();

        private static void AppMain(Application app, string[] args)
        {
            var stop = new CancellationTokenSource();

            async void Start()
            {
                await Task.Delay(10);
                var splashViewModel = new SplashWindowViewModel();
                var splash = new SplashWindow { DataContext = splashViewModel };
                splash.Show();

                IClassicDesktopStyleApplicationLifetime desktop = new ClassicDesktopStyleApplicationLifetime();
                app.ApplicationLifetime = desktop;

                desktop.MainWindow = await GetMainWindowAsync(splashViewModel);
                desktop.MainWindow.Closed += (_, __) => stop.Cancel();
                desktop.MainWindow.Show();
                desktop.MainWindow.Activate();
                splash.Close();
            }
            Start();
            app.Run(stop.Token);
        }

        static async Task<MainWindow> GetMainWindowAsync(SplashWindowViewModel splashViewModel)
        {
            // Initialize here
            await Task.Run(()=> splashViewModel.StartupProgressText = "Loading MainWindow");
            return new MainWindow() { DataContext = new MainWindowViewModel() };
        }
    }

Splash Window View Model:

    public class SplashWindowViewModel:ViewModelBase
    {
        public SplashWindowViewModel()
        {
            _startupProgressText = "Loading...";
        }

        private string _startupProgressText;

        public string StartupProgressText
        {
            get { return _startupProgressText; }
            set => this.RaiseAndSetIfChanged(ref _startupProgressText, value);
        }

    }

Splash Window:

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:vm="clr-namespace:oltk.ViewModels;assembly=oltk"
        mc:Ignorable="d" d:DesignWidth="400" d:DesignHeight="200"
        x:Class="oltk.Views.SplashWindow"
        Title="Loading OLTK"
        WindowStartupLocation="CenterScreen" HasSystemDecorations="False" CanResize="False" Topmost="True"
        Width="400" Height="200">

  <Design.DataContext>
    <vm:SplashWindowViewModel/>
  </Design.DataContext>

  <StackPanel Background="White">
    <TextBlock FontFamily="Arial" FontStyle="Normal" Foreground="Black" VerticalAlignment="Center" HorizontalAlignment="Center">Testing</TextBlock>
      <TextBlock VerticalAlignment="Center" HorizontalAlignment="Center" Text="{Binding StartupProgressText}"/>
  </StackPanel>
</Window>

I see the app running in the Taskbar once the splash.Show() is called (albeit with no icon - just an empty square). Mousing over it, it has the correct window title from my SplashWindow but the window thumbnail is black/empty. The SplashWindow does not display. If I remove the line splash.Close();, then the SplashWIndow appears at the same time as the MainWindow.

Am I on the right track with this or is there a better way to do this?
How can I make the SplashWindow appear at the correct time?
Thanks
Chris

[renrutsirhc]

OK - Ignore this - it turns out this code is working just fine. Adding await Task.Delay(1); directly after splash.Show() causes the splash screen to show much quicker!