COMException: 事件無法啟動任何訂閱者 (Exception from HRESULT: 0x80040201)
   於 MS.Win32.UnsafeNativeMethods.ITextStoreACPSink.OnTextChange(OnTextChangeFlags flags, TS_TEXTCHANGE& change)
   於 System.Windows.Documents.TextStore.OnTextContainerChange(Object sender, TextContainerChangeEventArgs args)
   於 System.Windows.Documents.TextContainerChangeEventHandler.Invoke(Object sender, TextContainerChangeEventArgs e)
   於 System.Windows.Documents.TextContainer.FireChangeEvent(TextPointer startPosition, TextPointer endPosition, Int32 symbolCount, Int32 leftEdgeCharCount, Int32 childCharCount, PrecursorTextChangeType precursorTextChange, DependencyProperty property, Boolean affectsRenderOnly)
   於 System.Windows.Documents.TextContainer.AddChange(TextPointer startPosition, TextPointer endPosition, Int32 symbolCount, Int32 leftEdgeCharCount, Int32 childCharCount, PrecursorTextChangeType textChange, DependencyProperty property, Boolean affectsRenderOnly)
   於 System.Windows.Documents.TextContainer.DeleteContentInternal(TextPointer startPosition, TextPointer endPosition)
   於 System.Windows.Documents.TextRangeEdit.DeleteContentBetweenPositions(TextPointer one, TextPointer two)
   於 System.Windows.Documents.TextRangeEdit.DeleteParagraphContent(ITextPointer start, ITextPointer end)
   於 System.Windows.Documents.TextRangeEditTables.DeleteContent(TextPointer start, TextPointer end)
   於 System.Windows.Documents.TextPointer.System.Windows.Documents.ITextPointer.DeleteContentToPosition(ITextPointer limit)
   於 System.Windows.Documents.TextEditorTyping.OnBackspace(Object sender, ExecutedRoutedEventArgs args)
   於 System.Windows.Input.CommandBinding.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
   於 System.Windows.Input.CommandManager.ExecuteCommandBinding(Object sender, ExecutedRoutedEventArgs e, CommandBinding commandBinding)
   於 System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
   於 System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
   於 System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   於 System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   於 System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   於 System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   於 System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   於 System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)
   於 System.Windows.Input.CommandManager.TranslateInput(IInputElement targetElement, InputEventArgs inputEventArgs)
   於 System.Windows.UIElement.OnKeyDownThunk(Object sender, KeyEventArgs e)
   於 System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   於 System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   於 System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   於 System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   於 System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   於 System.Windows.Input.InputManager.ProcessStagingArea()
   於 System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   於 System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   於 System.Windows.Interop.HwndKeyboardInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawKeyboardActions actions, Int32 scanCode, Boolean isExtendedKey, Boolean isSystemKey, Int32 virtualKey)
   於 System.Windows.Interop.HwndKeyboardInputProvider.ProcessKeyAction(MSG& msg, Boolean& handled)
   於 System.Windows.Interop.HwndSource.CriticalTranslateAccelerator(MSG& msg, ModifierKeys modifiers)
   於 System.Windows.Interop.HwndSource.OnPreprocessMessage(Object param)
   於 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   於 System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)