2017-03-03 4 views
-1

WPF에서 데스크톱 응용 프로그램을 만들고 UserControl의 코드에서 메서드가 변경된 메서드에서 트리거되는 오류를 디버깅합니다.예외가 발생하면 클래스가 null이됩니다.

내가이 메서드 위로 줄을 가리키고 해당 형식의 줄에 중단 점을 넣으면 올바른 형식의 UserControl이 표시됩니다. 하지만 그 줄을 실행하면 객체 참조 null 예외가 발생하며 null 인 경우 UserControl이 삭제되었음을 나타냅니다. 스택 추적이

at FACTAsync.Views.MonitoringPlanListView.ErrorPanel_OnIsVisibleChanged(Object sender, DependencyPropertyChangedEventArgs e) in C:\TFS\CAMD Software Tools\FACT\FACTAsync\FACTAsync\Views\MonitoringPlanListView.xaml.cs:line 44 
    at System.Windows.UIElement.RaiseDependencyPropertyChanged(EventPrivateKey key, DependencyPropertyChangedEventArgs args) 
    at System.Windows.UIElement.OnIsVisibleChanged(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.UIElement.UpdateIsVisibleCache() 
    at System.Windows.UIElement.OnVisibilityChanged(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 System.Windows.Data.BindingExpression.ScheduleTransfer(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.PropertyPathWorker.OnDependencyPropertyChanged(DependencyObject d, DependencyProperty dp, Boolean isASubPropertyChange) 
    at MS.Internal.Data.ClrBindingWorker.OnSourceInvalidation(DependencyObject d, DependencyProperty dp, Boolean isASubPropertyChange) 
    at System.Windows.Data.BindingExpression.HandlePropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args) 
    at System.Windows.Data.BindingExpressionBase.OnPropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args) 
    at System.Windows.Data.BindingExpression.OnPropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args) 
    at System.Windows.DependentList.InvalidateDependents(DependencyObject source, DependencyPropertyChangedEventArgs sourceArgs) 
    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.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal) 
    at System.Windows.DependencyObject.SetCurrentValueInternal(DependencyProperty dp, Object value) 
    at System.Windows.Controls.Primitives.ToggleButton.OnToggle() 
    at System.Windows.Controls.Primitives.ToggleButton.OnClick() 
    at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e) 
    at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e) 
    at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
    at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
    at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs) 
    at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 
    at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent) 
    at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e) 
    at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
    at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
    at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs) 
    at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 
    at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) 
    at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args) 
    at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted) 
    at System.Windows.Input.InputManager.ProcessStagingArea() 
    at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) 
    at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport) 
    at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel) 
    at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
    at System.Windows.Interop.HwndSource.InputFilterMessage(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) 
    at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs) 
    at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam) 
    at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) 
    at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) 
    at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) 
    at System.Windows.Application.RunDispatcher(Object ignore) 
    at System.Windows.Application.RunInternal(Window window) 
    at System.Windows.Application.Run(Window window) 
    at FACTAsync.Program.Main() in C:\TFS\CAMD Software Tools\FACT\FACTAsync\FACTAsync\Program.cs:line 60 
    at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args) 
    at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) 
    at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() 
    at System.Threading.ThreadHelper.ThreadStart_Context(Object state) 
    at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 
    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 
    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) 
    at System.Threading.ThreadHelper.ThreadStart() 
+0

설명은 확장 토론이 아닙니다. 이 대화는 [채팅으로 이동되었습니다] (http://chat.stackoverflow.com/rooms/137221/discussion-on-question-by-kleineg-class-becomes-null-when-exception-is-thrown). –

답변

1

FrameworkElementAutomationPeer.FromElement가 null 반환 편집

    <TextBlock x:Name="ErrorMessage" 
           Uid="7" 
           VerticalAlignment="Center" 
           Foreground="Red" 
           Text="Error message" 
           ToolTip="Error message"        
           AutomationProperties.HelpText="Error message" 
           AutomationProperties.Name="Error message" 

           Focusable="True" 
           FocusManager.IsFocusScope="True" 
           FocusVisualStyle="{StaticResource MyFocusVisual}" 
           FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Mode=Self}}" 
         /> 

다음, 그에 RaiseAutomationEvent를 호출하면 NullReferenceException의 원인으로

의 ErrorMessage의 정의입니다.

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