<Application
    x:Class="DesktopApp.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ui="http://schemas.lepo.co/wpfui/2022/xaml"
    DispatcherUnhandledException="OnDispatcherUnhandledException"
    Exit="OnExit"
    Startup="OnStartup">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ui:ThemesDictionary Theme="Dark" />
                <ui:ControlsDictionary />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

public partial class App
    {
        // The.NET Generic Host provides dependency injection, configuration, logging, and other services.
        // https://docs.microsoft.com/dotnet/core/extensions/generic-host
        // https://docs.microsoft.com/dotnet/core/extensions/dependency-injection
        // https://docs.microsoft.com/dotnet/core/extensions/configuration
        // https://docs.microsoft.com/dotnet/core/extensions/logging
        private static readonly IHost _host = Host
            .CreateDefaultBuilder()
            .ConfigureAppConfiguration(c => { c.SetBasePath(Path.GetDirectoryName(Assembly.GetEntryAssembly()!.Location)); })
            .ConfigureServices((context, services) =>
            {
                services.AddHostedService<ApplicationHostService>();

                services.AddSingleton<MainWindow>();
                services.AddSingleton<MainWindowViewModel>();
                services.AddSingleton<INavigationService, NavigationService>();
                services.AddSingleton<ISnackbarService, SnackbarService>();
                services.AddSingleton<IContentDialogService, ContentDialogService>();

                services.AddSingleton<DashboardPage>();
                services.AddSingleton<DashboardViewModel>();
                services.AddSingleton<DataPage>();
                services.AddSingleton<DataViewModel>();
                services.AddSingleton<SettingsPage>();
                services.AddSingleton<SettingsViewModel>();
            }).Build();

        /// <summary>
        /// Gets registered service.
        /// </summary>
        /// <typeparam name="T">Type of the service to get.</typeparam>
        /// <returns>Instance of the service or <see langword="null"/>.</returns>
        public static T GetService<T>()
            where T : class
        {
            return _host.Services.GetService(typeof(T)) as T;
        }

        /// <summary>
        /// Occurs when the application is loading.
        /// </summary>
        private void OnStartup(object sender, StartupEventArgs e)
        {
            _host.Start();
            Wpf.Ui.Appearance.Theme.Apply(Wpf.Ui.Appearance.ThemeType.Dark);
        }

        /// <summary>
        /// Occurs when the application is closing.
        /// </summary>
        private async void OnExit(object sender, ExitEventArgs e)
        {
            await _host.StopAsync();

            _host.Dispose();
        }

        /// <summary>
        /// Occurs when an exception is thrown by an application but not handled.
        /// </summary>
        private void OnDispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
        {

            // For more info see https://docs.microsoft.com/en-us/dotnet/api/system.windows.application.dispatcherunhandledexception?view=windowsdesktop-6.0
        }