System.Windows.Vector.Normalize() can throw DivideByZeroException

• .NET Core Version: 6.0
• Windows version: Windows 10

I have only the exception stack trace collected automatically from one of my clients. No other system information is available.

I do not know how to reproduce this issue.

I hope that this stack trace would be useful for some research.

Vector class can throw this exception when its_x and _y fields are equal to 0.

Line of code that raised the exception:

DropDown.IsOpen = true;

where DropDown has type System.Windows.Controls.ContextMenu.

System.DivideByZeroException: Attempted to divide by zero.
at void System.Windows.Vector.Normalize()
at void System.Windows.Controls.Primitives.Popup.UpdatePosition()
at void System.Windows.Controls.Primitives.Popup.Reposition()
at void System.Windows.Controls.Primitives.Popup.OnWindowResize(object sender, AutoResizedEventArgs e)
at void System.Windows.Interop.HwndSource.Resize(Size newSize)
at void System.Windows.Interop.HwndSource.OnLayoutUpdated(object obj, EventArgs args)
at void System.Windows.ContextLayoutManager.fireLayoutUpdateEvent()
at void System.Windows.ContextLayoutManager.UpdateLayout()
at void System.Windows.Interop.HwndSource.SetLayoutSize()
at void System.Windows.Interop.HwndSource.set_RootVisualInternal(Visual value)
at void System.Windows.Interop.HwndSource.set_RootVisual(Visual value)
at void System.Windows.Controls.Primitives.Popup.SetRootVisualToPopupRoot()
at void System.Windows.Controls.Primitives.Popup.CreateWindow(bool asyncCall)
at void System.Windows.Controls.Primitives.Popup.OnIsOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
at void System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at void System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at void System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at UpdateResult System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, ref EffectiveValueEntry newEntry, bool coerceWithDeferredReference, bool coerceWithCurrentValue, OperationType operationType)
at void System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, object value, PropertyMetadata metadata, bool coerceWithDeferredReference, bool coerceWithCurrentValue, OperationType operationType, bool isInternal)
at void System.Windows.DependencyObject.SetValue(DependencyProperty dp, object value)
at BindingExpressionBase System.Windows.Data.BindingOperations.SetBinding(DependencyObject target, DependencyProperty dp, BindingBase binding)
at void System.Windows.Controls.Primitives.Popup.CreateRootPopupInternal(Popup popup, UIElement child, bool bindTreatMousePlacementAsBottomProperty)
at void System.Windows.Controls.ContextMenu.HookupParentPopup()
at void System.Windows.Controls.ContextMenu.OnIsOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
at void System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at void System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at void System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at UpdateResult System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, ref EffectiveValueEntry newEntry, bool coerceWithDeferredReference, bool coerceWithCurrentValue, OperationType operationType)
at void System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, object value, PropertyMetadata metadata, bool coerceWithDeferredReference, bool coerceWithCurrentValue, OperationType operationType, bool isInternal)
at void System.Windows.DependencyObject.SetValue(DependencyProperty dp, object value)
at void System.Windows.Controls.ContextMenu.set_IsOpen(bool value)

[singhashish-wpf]

@VladimirKhil Thanks for the issue. For now, we will be closing this. For the next time it’ll be great if we have a memory dump or a reliable minimal repro to check this. Thanks @miloush for the follow up 👍

[VladimirKhil]

That sounds much more plausible. Is your application calling any native code around this codepath?

No, there are no native calls nearby. But there are a few in the whole application. One of it or maybe some native call in WPF itself could be the root cause.

Sorry, but it seems that the root cause could not be discovered easily. The problem is very rare. So maybe it is better to just close the issue until any new similar cases happen.