Logo Questions Linux Laravel Mysql Ubuntu Git Menu
HTML CSS JAVASCRIPT SQL PYTHON PHP BOOTSTRAP JAVA JQUERY R React Kotlin
 

How to debug NullReferenceException in PresentationFramework?

Tags:

.net

exception

nullreferenceexception

wpf

treeview

My .NET 4 application uses the WPF TreeView which I have enhanced to enable keyboard navigation and lazy loading, for example. My problem is that, very rarely, the exception shown below is thrown. This happened to me only once during months of development, and I have bug reports from several customers who also get this once in a while. It is so rare that I cannot change something, play around with the app for a while and know if the problem is gone or not.

But my main question is: the stack trace shows only Microsoft code, there is nothing from me in there. Is this a bug in .NET/WPF? And are there any chances of getting to the root cause?

Type: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: PresentationFramework
Stack trace:    at System.Windows.Controls.ItemContainerGenerator.ContainerFromIndex(Int32 index)
  at System.Windows.Controls.TreeViewItem.FindNextFocusableItem(Boolean walkIntoSubtree)
  at System.Windows.Controls.TreeViewItem.InternalPredictFocus(FocusNavigationDirection direction)
  at System.Windows.Controls.VirtualizingStackPanel.FocusChanged(KeyboardFocusChangedEventArgs e)
  at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
  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.Input.InputManager.ProcessStagingArea()
  at System.Windows.Input.KeyboardDevice.ChangeFocus(DependencyObject focus, Int32 timestamp)
  at System.Windows.Input.KeyboardDevice.Focus(DependencyObject focus, Boolean askOld, Boolean askNew, Boolean forceToNullIfFailed)
  at System.Windows.Input.KeyboardDevice.Focus(IInputElement element)
  at System.Windows.UIElement.Focus()
  at System.Windows.Controls.TreeViewItem.OnItemsChanged(NotifyCollectionChangedEventArgs e)
  at System.Windows.Controls.ItemsControl.OnItemCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
  at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
  at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
  at System.Windows.Controls.ItemCollection.SetCollectionView(CollectionView view)
  at System.Windows.Controls.ItemsControl.OnItemsSourceChanged(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.Data.BindingExpressionBase.Invalidate(Boolean isASubPropertyChange)
  at System.Windows.Data.BindingExpression.Activate(Object item)
  at System.Windows.Data.BindingExpression.OnDataContextChanged(DependencyObject contextElement)
  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.SetValue(DependencyProperty dp, Object value)
  at System.Windows.Controls.ItemContainerGenerator.System.Windows.Controls.Primitives.IItemContainerGenerator.RemoveAll()
  at System.Windows.Controls.VirtualizingStackPanel.ClearAllContainers(ItemsControl itemsControl)
  at System.Windows.Controls.ItemsControl.MS.Internal.Controls.IGeneratorHost.ClearContainerForItem(DependencyObject container, Object item)
  at System.Windows.Controls.ItemContainerGenerator.UnlinkContainerFromItem(DependencyObject container, Object item)
  at System.Windows.Controls.ItemContainerGenerator.Remove(GeneratorPosition position, Int32 count, Boolean isRecycling)
  at System.Windows.Controls.VirtualizingStackPanel.CleanupRange(IList children, IItemContainerGenerator generator, Int32 startIndex, Int32 count)
  at System.Windows.Controls.VirtualizingStackPanel.CleanupContainers(Int32 firstViewport, ItemsControl itemsControl)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.TreeViewItem.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.TreeViewItem.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.TreeViewItem.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.TreeViewItem.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.TreeViewItem.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Border.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Control.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
  at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
  at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Border.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.Controls.Control.MeasureOverride(Size constraint)
  at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
  at System.Windows.UIElement.Measure(Size availableSize)
  at System.Windows.ContextLayoutManager.UpdateLayout()
  at System.Windows.Interop.HwndSource.Process_WM_SIZE(UIElement rootUIElement, IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam)
  at System.Windows.Interop.HwndSource.LayoutFilterMessage(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 MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
Target: System.Windows.DependencyObject ContainerFromIndex(Int32)
Inner exception message:

Note: I have had this on my machine, too, which runs a fully patched Windows 7 x64.

like image 289
Helge Klein Avatar asked Oct 08 '22 22:10

Helge Klein

1 Answers

I've personally never uncovered a bug in WPF. However, stepping into the WPF code has frequently enabled me to trace the source of the problem back to myself.

Here are some MSDN articles on how to enable debugging Framework source:

  • Visual Studio 2008 version
  • Visual Studio 2010 version

Link to all versions: https://msdn.microsoft.com/en-us/library/cc667410.aspx

like image 177
Sean U Avatar answered Oct 13 '22 11:10

Sean U
Sign in to Comment

Related questions

Parsing JSON string to .NET Object
XML Repository; to Save() or not to Save()
How to set "run only if logged in" and "run as" with TaskScheduler in C#?
Is there a .NET port of the SED stream editor
Using Deleporter for cross process mocking
.Net app.config file ignored when under c:\ProgramFiles\
How to enumerate all HID devices? C#
System.Drawing.FontFamily.GenericSansSerif - What affects the underlying font it selects?
What are some of the alternatives to the Event-based Asynchronous Pattern?
Programmatically invoking validation on a TextBox
Using Directive to declare a pseudo-type in C#
Simple C# Array throwing OutOfMemory exception
Pass VB6 object to .NET object via interop?
Starting remote Windows services with ServiceController and impersonation
RavenDb Skips items when there are no filtering conditions
Product trademark name begs for class/namespace with same name
How do I enable Code Coverage for .NET Standard Library (2.0) project in VSTS (CI)
What is awaitable?
Why is the implementation of events in C# not using a weak event pattern by default?
How can I get current values of locals and parameters on the stack?

Donate For Us

If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!