CheckBottomScrollableBounds() - Object reference not set to an instance of an object

[goodbar]

Getting a frequent error on loading several raddataboundlistboxes.  The error does not occur the first time I load them, but can occur randomly after the first load upon updating the source collection.  I have confirmed that the source collection is not null. 



Error:  System.NullReferenceException

Message:  "Object reference not set to an instance of an object."

Source:  Telerik.Windows.Controls.Primitives

   at Telerik.Windows.Controls.VirtualizationStrategy.CheckBottomScrollableBounds()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.ManageViewport()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.BalanceVisualSpace()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.CleanupAfterCollectionReset()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.OnCollectionReset()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.UpdateViewportOnItemsChange(NotifyCollectionChangedEventArgs e)

   at Telerik.Windows.Controls.RadVirtualizingDataControl.OnItemsChanged(NotifyCollectionChangedEventArgs e)

   at Telerik.Windows.Controls.RadDataBoundListBox.OnItemsChanged(NotifyCollectionChangedEventArgs e)

   at Telerik.Windows.Controls.Primitives.DataControlBase.OnListSourceCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)

   at Telerik.Windows.Data.RadListSource.OnCollectionChanged(NotifyCollectionChangedEventArgs e)

   at Telerik.Windows.Data.RadListSource.RefreshOverride()

   at Telerik.Windows.Data.RadListSource.Refresh()

   at Telerik.Windows.Data.RadListSource.AttachData(IEnumerable data)

   at Telerik.Windows.Data.RadListSource.SetSource(IEnumerable value)

   at Telerik.Windows.Data.RadListSource.set_SourceCollection(IEnumerable value)

   at Telerik.Windows.Controls.RadDataBoundListBox.OnItemsSourceChanged(IEnumerable oldSource)

   at Telerik.Windows.Controls.Primitives.DataControlBase.OnItemsSourceChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)

   at System.Windows.DependencyObject.RaisePropertyChangeNotifications(DependencyProperty dp, Object oldValue, Object newValue)

   at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)

   at System.Windows.DependencyObject.RefreshExpression(DependencyProperty dp)

   at System.Windows.Data.BindingExpression.SendDataToTarget()

   at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)

   at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)

   at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)

   at System.Windows.CLRPropertyListener.SourcePropertyChanged(Object sender, PropertyChangedEventArgs args)

   at System.Windows.Data.WeakPropertyChangedListener.PropertyChangedCallback(Object sender, PropertyChangedEventArgs args)

   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)

[Deyan]

Hello Joe,

Thanks for writing and for reporting this issue.

Currently we are not aware of similar issues and it will be great if you manage to isolate the case into a sample project and send it to us for further investigation. This will help us directly debug the source code and see what exactly happens.

Thanks for your time.

Regards,
Deyan
Telerik