启动画面支持加载进度

Question

我有以下将Caliburn Micro用于我的MVVM框架的引导程序类

public class Bootstrapper : BootstrapperBase
{
    private List<Assembly> priorityAssemblies;

    public Bootstrapper()
    {
        PreInitialize();
        Initialize();
    }

    protected virtual void PreInitialize() { }

    protected override void Configure()
    {
        var directoryCatalog = new DirectoryCatalog(@"./");
        AssemblySource.Instance.AddRange(
             directoryCatalog.Parts
                  .Select(part => ReflectionModelServices.GetPartType(part).Value.Assembly)
                  .Where(assembly => !AssemblySource.Instance.Contains(assembly)));

        priorityAssemblies = SelectAssemblies().ToList();
        var priorityCatalog = new AggregateCatalog(priorityAssemblies.Select(x => new AssemblyCatalog(x)));
        var priorityProvider = new CatalogExportProvider(priorityCatalog);

        // Now get all other assemblies (excluding the priority assemblies).
        var mainCatalog = new AggregateCatalog(
            AssemblySource.Instance
                .Where(assembly => !priorityAssemblies.Contains(assembly))
                .Select(x => new AssemblyCatalog(x)));
        var mainProvider = new CatalogExportProvider(mainCatalog);

        Container = new CompositionContainer(priorityProvider, mainProvider);
        priorityProvider.SourceProvider = Container;
        mainProvider.SourceProvider = Container;

        var batch = new CompositionBatch();

        BindServices(batch);
        batch.AddExportedValue(mainCatalog);

        Container.Compose(batch);
    }

    protected virtual void BindServices(CompositionBatch batch)
    {
        batch.AddExportedValue<IWindowManager>(new WindowManager());
        batch.AddExportedValue<IEventAggregator>(new EventAggregator());
        batch.AddExportedValue(Container);
        batch.AddExportedValue(this);
    }

    protected override object GetInstance(Type serviceType, string key)
    {
        String contract = String.IsNullOrEmpty(key) ?
            AttributedModelServices.GetContractName(serviceType) :
            key;
        var exports = Container.GetExports<object>(contract);

        if (exports.Any())
            return exports.First().Value;

        throw new Exception(
            String.Format("Could not locate any instances of contract {0}.", contract));
    }

    protected override IEnumerable<object> GetAllInstances(Type serviceType)
    {
        return Container.GetExportedValues<object>(
            AttributedModelServices.GetContractName(serviceType));
    }

    protected override void BuildUp(object instance)
    {
        Container.SatisfyImportsOnce(instance);
    }

    protected override void OnStartup(object sender, StartupEventArgs suea)
    {
        base.OnStartup(sender, suea);
        DisplayRootViewFor<IMainWindow>();
    }

    protected override IEnumerable<Assembly> SelectAssemblies()
    {
        return new[] { Assembly.GetEntryAssembly() };
    }

    protected CompositionContainer Container { get; set; }

    internal IList<Assembly> PriorityAssemblies
    {
        get { return priorityAssemblies; }
    }
}

很好，可以很好地工作，可以加载导出的模块等。现在，我想实现一个显示进度的启动屏幕（进度条和加载的导出信息等），所以我不希望使用标准的WPF SplashScreen仅仅是静态图像。

现在，我已经看到了带有外壳屏蔽导体的Custom caliburn.micro初始屏幕，但对我而言，这不是问题，只有在OnStartup之后才加载MEF导出。

因此，我添加了以下SplashScreenManager类

[Export(typeof(ISplashScreenManager))]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class SplashScreenManager : ISplashScreenManager
{
    private IWindowManager windowManager;
    private ISplashScreen splashScreen;

    private Thread splashThread;
    private Dispatcher splashDispacher;

    [ImportingConstructor]
    public SplashScreenManager(IWindowManager windowManager, ISplashScreen splashScreen)
    {
        if (windowManager == null)
            throw new ArgumentNullException("windowManager cannot be null");

        if (splashScreen == null)
            throw new ArgumentNullException("splashScreen cannot be null");

        this.windowManager = windowManager;
        this.splashScreen = splashScreen;
    }

    public void ShowSplashScreen()
    {
        splashDispacher = null;
        if (splashThread == null)
        {
            splashThread = new Thread(new ThreadStart(DoShowSplashScreen));
            splashThread.SetApartmentState(ApartmentState.STA);
            splashThread.IsBackground = true;
            splashThread.Start();
            Log.Trace("Splash screen thread started");
        }
    }

    private void DoShowSplashScreen()
    {
        splashDispacher = Dispatcher.CurrentDispatcher;
        SynchronizationContext.SetSynchronizationContext(
            new DispatcherSynchronizationContext(splashDispacher));

        splashScreen.Closed += (s, e) =>
            splashDispacher.BeginInvokeShutdown(DispatcherPriority.Background);
        Application.Current.Dispatcher.BeginInvoke(
            new System.Action(delegate { windowManager.ShowWindow(splashScreen); }));

        Dispatcher.Run();
        Log.Trace("Splash screen shown and dispatcher started");
    }

    public void CloseSplashScreen()
    {
        if (splashDispacher != null)
        {
            splashDispacher.BeginInvoke(
                new System.Action(delegate { splashScreen.Close(); }));
            Log.Trace("Splash screen close requested");
        }
    }

    public ISplashScreen SplashScreen
    {
        get { return splashScreen; }
    }
}

尝试使用Caliburn的IWindowManager在后台线程上显示启动屏幕。 ISplashScreenManager在哪里

public interface ISplashScreenManager
{
    void ShowSplashScreen();

    void CloseSplashScreen();

    ISplashScreen SplashScreen { get; }
}

然后我们有ISplashScreen[ViewModel]实现

[Export(typeof(ISplashScreen))]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class SplashScreenViewModel : Screen, ISplashScreen, ISupportProgress
{
    // Code to provide updates to the view etc. 
}

此时将ISplashScreen作为空标记接口。

所以我的问题是我如何正确地排序SplashScreenViewModel的调用，以便在启动模块GetInstance方法中加载模块时显示初始屏幕？

我尝试做类似的事情

protected override void OnStartup(object sender, StartupEventArgs suea)
{
    var splashManager = Container.GetExportedValue<ISplashScreenManager>();
    var windowManager = IoC.Get<IWindowManager>();
    windowManager.ShowWindow(splashManager.SplashScreen);

    base.OnStartup(sender, suea);
    DisplayRootViewFor<IMainWindow>();

    splashManager.SplashScreen.TryClose();
}

但这会立即关闭启动画面，并且没有利用我的多线程代码在SplashScreenManager显示启动画面。

我愿意对代码进行大量修改以执行我想要的操作，但是此时我似乎可以得到正确的组合。 我想避免过于深入地研究线程并使用ManualResetEvent ，然后再请高级人员就如何进行最佳处理提出建议。

谢谢你的时间。

---

部分解决方案：我的引导程序类中的OnStartup方法中现在有以下代码

protected override void OnStartup(object sender, StartupEventArgs suea)
{
    splashScreenManager = Container.GetExportedValue<ISplashScreenManager>();
    splashScreenManager.ShowSplashScreen();

    Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
    Application.Current.MainWindow = null;

    base.OnStartup(sender, suea);
    DisplayRootViewFor<IMainWindow>();

    // I have also tried this.
    Application.Current.Dispatcher.Invoke(() => DisplayRootViewFor<IMainWindow>());

    splashScreenManager.CloseSplashScreen();
}

SplashScreenManager类是

[Export(typeof(ISplashScreenManager))]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class SplashScreenManager : ISplashScreenManager
{
    private IWindowManager windowManager;
    private ISplashScreenViewModel splashScreen;

    private Thread splashThread;
    private Dispatcher splashDispacher;

    public void ShowSplashScreen()
    {
        splashDispacher = null;
        if (splashThread == null)
        {
            splashThread = new Thread(new ThreadStart(DoShowSplashScreen));
            splashThread.SetApartmentState(ApartmentState.STA);
            splashThread.IsBackground = true;
            splashThread.Name = "SplashThread"; 
            splashThread.Start();
            Log.Trace("Splash screen thread started");
        }
    }

    private void DoShowSplashScreen()
    {
        // Get the splash vm on the splashThread.
        splashScreen = IoC.Get<ISplashScreenViewModel>();

        splashDispacher = Dispatcher.CurrentDispatcher;
        SynchronizationContext.SetSynchronizationContext(
            new DispatcherSynchronizationContext(splashDispacher));

        splashScreen.Closed += (s, e) =>
            splashDispacher.BeginInvokeShutdown(DispatcherPriority.Background);
        splashScreen.Show();

        Dispatcher.Run();
        Log.Trace("Splash screen shown and dispatcher started");
    }

    public void CloseSplashScreen()
    {
        if (splashDispacher != null)
        {
            splashScreen.Close();
            Log.Trace("Splash screen close requested");
        }
    }

    public ISplashScreenViewModel SplashScreen
    {
        get { return splashScreen; }
    }
}

现在，它会显示启动屏幕，其中包含不确定的进度条（尚未连接消息）

现在的问题是，当我们下线时

DisplayRootViewFor<IMainWindow>();

它将引发InvalidOperationException与消息

调用线程无法访问该对象，因为其他线程拥有它。

堆栈跟踪为

在d：\\ projects \\ git \\ MahApps.Metro \\ src \\中的MahApps.Metro.Controls.MetroWindow.get_Flyouts（）中的System.Windows.DependencyObject.GetValue（DependencyProperty dp）中的System.Windows.Threading.Dispatcher.VerifyAccess（）中MahApps.Metro.Controls.MetroWindow.cs上的MahApps.Metro \\ MahApps.Metro.Shared \\ Controls \\ MetroWindow.cs：线269在d：\\ projects \\ git \\ MahApps.Metro \\ src \\ MahApps .Metro \\ MahApps.Metro.Shared \\ Controls \\ MetroWindow.cs：System.EventHandler 1.Invoke(Object sender, TEventArgs e) at MahApps.Metro.Controls.SafeRaise.Raise[T](EventHandler线962 1.Invoke(Object sender, TEventArgs e) at MahApps.Metro.Controls.SafeRaise.Raise[T](EventHandler 1 eventToRaise，Object 1.Invoke(Object sender, TEventArgs e) at MahApps.Metro.Controls.SafeRaise.Raise[T](EventHandler d：\\ projects \\ git \\ MahApps.Metro \\ src \\ MahApps.Metro \\ MahApps.Metro.Shared \\ Controls \\ SafeRaise.cs：第26行，位于MahApps.Metro.ThemeManager.OnThemeChanged（Accent newAccent，AppTheme） newTheme）在d：\\ projects \\ git \\ MahApps.Metro \\ src \\ MahApps.Metro \\ MahApps.Metro.Shared \\ ThemeManager \\ ThemeManager.cs：行591处MahApps.Metro.ThemeManager.ChangeAppStyle（ResourceDic d，\\ projects \\ git \\ MahApps.Metro \\ src \\ MahApps.Metro \\ MahApps.Metro.Shared \\ ThemeManager \\ ThemeManager \\ ThemeManager.cs：第407行上的dtuary`2资源，元组newOldThemeInfo，Accent newAccent，AppTheme newTheme）。 .ThemeManager.ChangeAppStyle（Application app，d：\\ projects \\ git \\ MahApps.Metro \\ src \\ MahApps.Metro \\ MahApps.Metro.Shared \\ ThemeManager \\ ThemeManager.cs：line 345在d：\\ projects \\ git \\ MahApps.Metro.Shared .Themes.ThemeManager.SetCurrentTheme（String name）in F：\\ Camus \\ Augur \\ Src \\ Augur \\ Core \\ Themes \\ ThemeManager.cs：F 46中Augur.Modules.Shell.ViewModels.ShellViewModel.OnViewLoaded（Object view）的第46行:: Camus \\ Augur \\ Src \\ Augur \\ Modules \\ Shell \\ ViewModels \\ ShellViewModel.cs：Caliburn.Micro.XamlPlatformProvider上的第73行。<> c__DisplayClass11_0.b__0（Object s，RoutedEventArgs e）在Caliburn.Micro.View。<> System.Windows.UI.UIElement.RaiseEventImpl（Dep）上的c__DisplayClass8_0.b__0（Object s，RoutedEventArgs e）在System.Windows.EventRoute.InvokeHandlersImpl（Object source，RoutedEventArgs args，Boolean reRaised） endencyObject发送者，位于System.Windows.BroadcastEventHelper.BroadcastEvent（DependencyObject根，RoutedEvent routedEvent），位于System.Windows.BroadcastEventHelper.BroadcastLoadedEvent（对象根），位于System.Windows.Media的MS.Internal.LoadedOrUnloadedOperation.DoWork（）。 System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks（）处于System.Windows.Media.MediaContext.RenderMessageHandlerCore（Object resizedCompositionTarget）处于System.Windows.Media.MediaContext.RenderMessageHandler（Object resizedCompositionTarget）处于System.Windows。 System.Windows.Interop.HwndTarget.HandleMessage处的Interop.HwndTarget.OnResize（）（System.Windows.Interop.HwndSource.HwndTargetFilterMessage（IntPtr hwnd，Int32 msg，IntPtr lParam，IntPtr，IntPtr lParam，IntPtr lParam） MS.Win32.HwndSubclass.Di上的MS.Win32.HwndWrapper.WndProc（IntPtr hwnd，Int32 msg，IntPtr wParam，IntPtr lParam，Boolean＆处理） System.Windows.Threading.ExceptionWrapper.InternalRealCall（System.Windows.Threading.ExceptionWrapper.TryCatchWhen（Object source，Delegate callback，Object args，Int32 numArgs，Delegate catchHandler的委托回调，Object args，Int32 numArgs） ），位于MS.Win32.HwndSubclass.SubclassWndProc（IntPtr hwnd，Int32 msg，IntPtr lParam，IntPtr InParent，IntPtr lParam，IntPtr lParam，

我试图更改代码以使用应用程序调度程序并存储任务调度程序，并将其与Task一起使用以返回Gui线程。 我不确定为什么我会丢失线程上下文，我在做什么错以及如何解决？

修复尝试

splashScreenManager = Container.GetExportedValue<ISplashScreenManager>();
splashScreenManager.ShowSplashScreen();

Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
Application.Current.MainWindow = null;

base.OnStartup(sender, suea);
Application.Current.Dispatcher.Invoke(() => DisplayRootViewFor<IMainWindow>()); // Still throws the same exception.

要么

splashScreenManager = Container.GetExportedValue<ISplashScreenManager>();
splashScreenManager.ShowSplashScreen();

Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
Application.Current.MainWindow = null;

base.OnStartup(sender, suea);
Application.Current.Dispatcher.BeginInvoke(
    new System.Action(delegate { DisplayRootViewFor<IMainWindow>(); })); // Still throws the same exception.

和

TaskScheduler guiScheduler = TaskScheduler.FromCurrentSynchronizationContext();

splashScreenManager = Container.GetExportedValue<ISplashScreenManager>();
splashScreenManager.ShowSplashScreen();

Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
Application.Current.MainWindow = null;

Task.Factory.StartNew(() =>
{
    base.OnStartup(sender, suea);
    DisplayRootViewFor<IMainWindow>();
}, CancellationToken.None, 
   TaskCreationOptions.None, 
   guiScheduler);

有任何想法吗？

Answer 1

为什么不在OnStartup方法中首先在后台线程上显示初始屏幕窗口，然后在初始化完成后将其关闭呢？：

protected override async void OnStartup(object sender, StartupEventArgs suea)
{
    Application.Current.ShutdownMode = ShutdownMode.OnLastWindowClose;
    Window splashScreenWindow = null;
    Thread splashScreenWindowThread = new Thread(new ThreadStart(() =>
    {
        SynchronizationContext.SetSynchronizationContext(new DispatcherSynchronizationContext(Dispatcher.CurrentDispatcher));
        splashScreenWindow = new Window();
        splashScreenWindow.Content = new ProgressBar() { IsIndeterminate = true };
        splashScreenWindow.Closed += (ss, es) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background);
        splashScreenWindow.Show();
        Dispatcher.Run();
    }));
    splashScreenWindowThread.SetApartmentState(ApartmentState.STA);
    splashScreenWindowThread.IsBackground = true;
    splashScreenWindowThread.Start();

    base.OnStartup(sender, suea);
    //...
    splashScreenWindow.Dispatcher.BeginInvoke(new Action(() => splashScreenWindow.Close()));
}