显示闪屏曹景伟出现InvalidOperationException

Question

问题

我有一个使用Caliburn.Micro作为MVVM框架和MEF的“依赖注入”一个MVVM应用程序（在引号，因为我知道它不是严格意义上的DI容器） 。根据MEF在应用程序启动过程中正在执行的构图数量，此大型应用程序的构图过程开始花费越来越多的时间，因此我想使用动画启动画面。

下面我将概述我当前的代码显示在一个单独的线程启动画面，并尝试启动主要应用

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

    public Bootstrapper() 
    { 
     Initialize(); 
    } 

    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); 

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

     base.OnStartup(sender, suea); 
     DisplayRootViewFor<IMainWindow>(); // HERE is the Problem line. 

     splashScreenManager.CloseSplashScreen(); 
    } 

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

    protected CompositionContainer Container { get; set; } 

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

我ISplashScreenManager实现

[Export(typeof(ISplashScreenManager))] 
[PartCreationPolicy(CreationPolicy.NonShared)] 
public class SplashScreenManager : ISplashScreenManager 
{ 
    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"); 

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

    private void DoShowSplashScreen() 
    { 
     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) 
     { 
      splashDispacher.BeginInvokeShutdown(DispatcherPriority.Send); 
      splashScreen.Close(); 
      Log.Trace("Splash screen close requested"); 
     } 
    } 

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

其中ISplashScreenViewModel.Show()和ISplashScreenViewModel.Close()方法分别显示和关闭相应的视图。

错误

此代码似乎只要它启动在后台线程启动画面和飞溅的动漫作品等。然而，当代码返回引导程序行以及工作

DisplayRootViewFor<IMainWindow>(); 

抛出InvalidOperationException以下消息

调用线程不能访问此OBJ因为不同的线程拥有它。

堆栈跟踪是

在System.Windows.Threading.Dispatcher.VerifyAccess（）在System.Windows.DependencyObject.GetValue（的DependencyProperty DP）在MahApps.Metro.Controls.MetroWindow.get_Flyouts （）在d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ Controls \ MetroWindow.cs中：第269行MahApps.Metro.Controls.MetroWindow.ThemeManagerOnIsThemeChanged（Object sender，OnThemeChangedEventArgs e ）在d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ Controls \ MetroWindow.cs中：在System.EventHandler1.Invoke中的第962行（对象发件人，TEventArgs e） 位于MahApps。 Metro.Controls.SafeRaise在MahApps中的第26行：.Raise [T]（EventHandler1 eventToRaise，Object sender，T args）在d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ Controls \ SafeRaise.cs中。 Metro.ThemeManager.OnThemeChanged（Accent newAccent，AppTheme newTheme）在d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ ThemeManager \ ThemeManager.cs中：第591行，位于MahApps.Metro.ThemeManager .ChangeAppStyle（ResourceDictionary资源，Tuple`2 oldThemeInfo，Accent newAccent，AppTheme newTheme）在d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ ThemeManager \ ThemeManager.cs中：第407行MahApps.Metro.ThemeManager.ChangeAppStyle（Application application，Accent newAccent，AppTheme newTheme）in d：\ projects \ git \ MahApps.Metro \ src \ MahApps.Metro \ MahApps.Metro.Shared \ ThemeManager \ ThemeManager.cs：line 345 at在Augur.Modules.Shell.ViewModels.ShellViewModel.OnViewLoaded（Obj）中的第46行， F：\ Camus \ Augur \ Src \ Augur \ Modules \ Shell \ ViewModels \ ShellViewModel.cs：Caliburn.Micro.XamlPlatformProvider的第73行。在Caliburn.Micro.View上的c__DisplayClass11_0.b__0（Object s，RoutedEventArgs e）。 <> c_DisplayClass8_0.b__0（Object s，RoutedEventArgs e）在System.Windows.EventRoute。在System.Windows.BroadcastEventHelper.BroadcastEvent（DependencyObject root，RoutedEvent routedEvent）System.Windows.BroadcastEventHelper.BroadcastLoadedEvent（System.Windows.UIElement.RaiseEventImpl（DependencyObject sender，RoutedEventArgs args））上的InvokeHandlersImpl（Object source，RoutedEventArgs args，Boolean reRaised）对象根）在System.Windows.Media.MediaContext.FireLoadedPendingCallbacks（）在System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks（）在System.Windows.Media.MediaContext.RenderMessageHandlerCore（对象resizedCompositionTarget）在MS.Internal.LoadedOrUnloadedOperation.DoWork（） ）System.Windows.Media.MediaContext.RenderMessageHandler（Object resizedCompositionTarget）System.Windows.Interop.HwndTarget.OnResize（）System.Windows.Interop.HwndTarget.HandleMessage（WindowMessage msg，IntPtr wparam，IntPtr lparam）在系统。 Windows.Interop.HwndSource.HwndTargetFilterMessage（IntPtr hwnd，Int32 msg，IntPtr wParam，IntPtr lParam，布尔型（System.Windows.Threading.ExceptionWrapper.InternalRealCall）上的MS.Win32.HwndSubclass.DispatcherCallbackOperation（Object o）处的MS.Win32.HwndWrapper.WndProc（IntPtr hwnd，Int32 msg，IntPtr wParam，IntPtr lParam，布尔&已处理） （System.Windows.Threading.Dispatcher.LegacyInvokeImpl（DispatcherPriority priority，System.Windows.Threading.ExceptionWrapper.TryCatchWhen（Object source，Delegate callback，Object args，Int32 numArgs，Delegate catchHandler）时间跨度超时，代表方法中，在MS.Win32.HwndSubclass.SubclassWndProc（IntPtr的HWND，MSG的Int32，IntPtr的wParam中，IntPtr的LPARAM）对象指定参数时，的Int32 numArgs）

尝试的解决方案

我试图改变执行DisplayRootViewFor<IMainWindow>();如下

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

和

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

甚至

TaskScheduler guiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); 

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

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

试图强制使用的使用调度代码Gui MainThread。以上所有都会抛出同样的异常。

问题

1. 我如何可以调用DisplayRootViewFor<IMainWindow>()方法，避免此异常？

2. 这种显示动画效果的方法是合法吗？

谢谢你的时间。

---

编辑。我已经从令人敬畏的Hans Passant https://*.com/a/4078528/626442发现了这个答案。鉴于此，我试图添加应用程序static App() { } ctor。

static App() 
{ 
    // Other stuff. 
    Microsoft.Win32.SystemEvents.UserPreferenceChanged += delegate { }; 
} 

但（可能是意料之中），这并没有帮助我。在同一地点也有同样的例外...

Answer 1

您正在新后台线程上创建SplashScreenView的实例，但在主UI线程中调用MetroThemeManager.ChangeAppStyle类ThemeManager类。

因为MetroWindow类是你SplashScreenView你不能阻止它的内部预订至ThemeManager.IsThemeChanged事件，您可以通过调用MetroThemeManager.ChangeAppStyle内ThemeManager类触发父。

由于内部MetroWindow的ThemeManager.IsThemeChanged事件处理程序的代码不能在主UI线程是从线程闪屏不同的是创造了你应该为[1]派生SplashScreenView从标准Window类，以避免依赖执行MetroWindow或[2]避免拨打MetroThemeManager.ChangeAppStyle而您的SplashScreenView仍然存在。

注释掉两行代码是删除违规行为，请参阅下面的行。但显然，实际的解决方案需要在另一个层面上完成，见上文。

// this line is causing violation due to hidden dependency 
MetroThemeManager.ChangeAppStyle(Application.Current, metroAccent, metroTheme); 

// this line is causing an error when closing the splash screen 
splashDispacher.BeginInvokeShutdown(DispatcherPriority.Send);