locked
System.NullReferenceException on "IsDropDownOpen = true" of combobox RRS feed

  • Question

  • It happens when a User holds "Enter" key and selects items by "Up/Down" keys.

    System.NullReferenceException was unhandled
      HResult=-2147467261
      Message=Object reference not set to an instance of an object.
      Source=PresentationFramework
      StackTrace:
           at System.Windows.Controls.ComboBox.CoerceIsSelectionBoxHighlighted(Object o, Object value)
           at System.Windows.DependencyObject.ProcessCoerceValue(DependencyProperty dp, PropertyMetadata metadata, EntryIndex& entryIndex, Int32& targetIndex, EffectiveValueEntry& newEntry, EffectiveValueEntry& oldEntry, Object& oldValue, Object baseValue, Object controlValue, CoerceValueCallback coerceValueCallback, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, Boolean skipBaseValueChecks)
           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.CoerceValue(DependencyProperty dp)
           at System.Windows.Controls.ComboBox.OnIsDropDownOpenChanged(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.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
           at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)

    Wednesday, August 24, 2016 10:23 AM

Answers

  • A (rather hacky) workaround is mentioned in the link I pasted above.
    • Marked as answer by Booster1 Thursday, August 25, 2016 8:18 AM
    Wednesday, August 24, 2016 3:55 PM

All replies