c# - 引发属性更改事件的异常 "The operation completed successfully"

Question

我可能遇到了我见过的最无用的异常(在 VBA 之外)，一个 System.ComponentModel.Win32Exception: "The operation completed successfully"

堆栈跟踪:

   at MS.Win32.UnsafeNativeMethods.CreateWindowEx(Int32 dwExStyle, String lpszClassName, String lpszWindowName, Int32 style, Int32 x, Int32 y, Int32 width, Int32 height, HandleRef hWndParent, HandleRef hMenu, HandleRef hInst, Object pvParam)
   at MS.Win32.HwndWrapper..ctor(Int32 classStyle, Int32 style, Int32 exStyle, Int32 x, Int32 y, Int32 width, Int32 height, String name, IntPtr parent, HwndWrapperHook[] hooks)
   at System.Windows.Interop.HwndSource.Initialize(HwndSourceParameters parameters)
   at System.Windows.Interop.HwndSource..ctor(HwndSourceParameters parameters)
   at System.Windows.Controls.Primitives.Popup.PopupSecurityHelper.BuildWindow(Int32 x, Int32 y, Visual placementTarget, Boolean transparent, HwndSourceHook hook, AutoResizedEventHandler handler)
   at System.Windows.Controls.Primitives.Popup.BuildWindow(Visual targetVisual)
   at System.Windows.Controls.Primitives.Popup.CreateWindow(Boolean asyncCall)
   at System.Windows.Controls.Primitives.Popup.OnIsOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
   at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
   at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp, Boolean preserveCurrentValue)
   at System.Windows.Data.BindingExpressionBase.Invalidate(Boolean isASubPropertyChange)
   at System.Windows.Data.BindingExpression.TransferValue(Object newValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.ClrBindingWorker.NewValueAvailable(Boolean dependencySourcesChanged, Boolean initialValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.PropertyPathWorker.UpdateSourceValueState(Int32 k, ICollectionView collectionView, Object newValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.ClrBindingWorker.OnSourcePropertyChanged(Object o, String propName)
   at System.Windows.WeakEventManager.ListenerList`1.DeliverEvent(Object sender, EventArgs e, Type managerType)
   at System.ComponentModel.PropertyChangedEventManager.OnPropertyChanged(Object sender, PropertyChangedEventArgs args)
   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)
   at MVVMSeaCores.Controls.HelpTip.NotifyOfPropertyChange(String propertyName) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 140
   at MVVMSeaCores.Controls.HelpTip.set_IsOpen(Boolean value) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 181
   at MVVMSeaCores.Controls.HelpTipManager.OpenNext() in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 102
   at MVVMSeaCores.Controls.HelpTipManager.AddedToScreen(HelpTip helpTip) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 115
   at MVVMSeaCores.Controls.HelpTipManager.HelpTip_PropertyChanged(Object sender, PropertyChangedEventArgs e) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 67
   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)
   at MVVMSeaCores.Controls.HelpTip.NotifyOfPropertyChange(String propertyName) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 140
   at MVVMSeaCores.Controls.HelpTip.set_IsOnscreen(Boolean value) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpTip.cs:line 195
   at MVVMSeaCores.Controls.HelpPopup.View1_Loaded(Object sender, RoutedEventArgs e) in D:\Projects\MVVMSeaCores\MVVMSeaCores\Controls\HelpPopup.xaml.cs:line 181
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root)
   at MS.Internal.LoadedOrUnloadedOperation.DoWork()
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

它始终在一行中发生，引发属性 IsOpen 的属性更改事件，但它似乎是随机发生的(有时一切正常!):

    private void NotifyOfPropertyChange(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName)); //<-here
        }
    }

对于上下文，IsOpen 绑定(bind)到弹出窗口的打开属性:

<Popup x:Name="Popup"
               DataContext="{Binding HelpTip, ElementName=userControl}"
               IsOpen="{Binding IsOpen}"
               StaysOpen="True" PopupAnimation="Fade"
               AllowsTransparency="True"
               Placement="{Binding Placement, ElementName=userControl}">

并且由一个静态类设置，它使用加载的事件来更新 IsOnscreen 属性和静态管理器类中的这个方法，确保一次只在屏幕上显示一个:

    private static void HelpTip_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        HelpTip helpTip = sender as HelpTip;
        if (helpTip != null)
        {
            //is this on screen or not?
            switch (e.PropertyName)
            {
                case "IsOnscreen":
                    //Update our onscreen lists and perform related behaviour
                    if (helpTip.IsOnscreen)
                    {
                        AddedToScreen(helpTip);
                    }
                    else
                    {
                        RemovedFromScreen(helpTip);
                    }
                    break;
                case "IsOpen":
                    lock (helpTip.Lock)
                    {
                        if (!helpTip.IsOpen)
                        {
                            OpenNext();
                        }
                    }
                    break;
            }
        }
    }

OpenNext 选择一个添加到屏幕的帮助提示并将其设置为使用 IsOpen 打开，这似乎是导致错误的原因。

一开始我以为可能是并发的问题，但是我去掉了所有线程并简化了一些东西，现在所有的事情实际上都在主线程上完成了。

我以前从未遇到过通知属性更改失败的情况，而且我也不知道可能出了什么问题。看看这个:System.ComponentModel.Win32Exception: The operation completed successfully这似乎与使用太多句柄有关(但我不确定我是如何达到打开和关闭 6 或 7 个弹出窗口的限制的 - edit: 还使用 taskmanager 检查过，它使用了大约 530在崩溃时。)或使用太大的图形或太大的缓冲区，我不认为我正在做这两种情况，因为这些弹出窗口只是少数组件。

Answer 1

不是很好的答案。但至少这是一种解决方法。该错误发生在 MS.Win32.UnsafeNativeMethods.CreateWindowEx 中，并且是 WPF 打开 Popup 的结果。这似乎是 WPF 中的一个错误，我几乎没有办法解决它。我仍然不确定为什么它会特别影响这些弹出窗口。 (其他弹出窗口工作正常，显然这不是弹出窗口的常见问题，但它对我来说非常可重现)。

我使用了以下(不是很愉快)解决方法。简单地使用绑定(bind)到它的 IsOpen 的东西关闭和打开弹出窗口是行不通的——一旦它打开时崩溃，弹出窗口就会完全损坏，直到它被卸载(改变 View )并再次加载。

所以解决方案是捕获错误，从它的父项中删除弹出窗口，然后安排它在调度线程上异步添加。我不得不停止简单地绑定(bind)到 IsOpen，而是监听代码隐藏中的属性更改。

我没有发现此错误的其他实例与互联网上的弹出窗口有关，尽管还有其他各种原因。这可能对将来的某些人有用:

    private void HelpPopup_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName.Equals("IsOpen"))
        {
            //re-try opening
            try {
                Popup.IsOpen = (sender as HelpTip).IsOpen;
            }
            catch (System.ComponentModel.Win32Exception ex)
            {
                Canvas parent = Popup.Parent as Canvas;
                Popup.IsOpen = false;
                parent.Children.Remove(Popup);
                Application.Current.Dispatcher.BeginInvoke(new Action(() => {
                    Popup.IsOpen = true;
                    parent.Children.Add(Popup);

                    //known method of updating position (for some reason it was incorrectly positioned on open)
                    var offset = Popup.HorizontalOffset;
                    Popup.HorizontalOffset = offset + 1;
                    Popup.HorizontalOffset = offset;

                }), DispatcherPriority.SystemIdle);

            }
        }
    }