Index was out of range

[Ola]

See that over the years there has been many issues with "Index out of range". Is this a general issue that has not been resolved yet? We are starting to use a WPF-application in production and as the load increases we get more and more of these exceptions. Looks like it can happen when we remove and item from a RadObservableCollection (or a ObservableCollection bound to a RadTimeline) and add an item right afterwards. Maybe combined with many entries in the collection.

Is there a workaround?

Here is a callstack:

2017-11-13 16:34:38,704 [106:1] ERROR Tennotech.Hilding.Watchman.App - Unhandled exception: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
2017-11-13 16:34:38,714 [106:1] DEBUG Tennotech.Hilding.Watchman.App - Stacktrace:
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at Telerik.Windows.Controls.ProjectedView`1.ObservableSourceListCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
   at System.Windows.Data.CompositeCollection.OnContainedCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Windows.WeakEventManager.ListenerList`1.DeliverEvent(Object sender, EventArgs e, Type managerType)
   at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
   at System.Windows.Data.CollectionContainer.OnContainedCollectionChanged(NotifyCollectionChangedEventArgs args)
   at System.Windows.WeakEventManager.ListenerList`1.DeliverEvent(Object sender, EventArgs e, Type managerType)
   at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
   at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
   at System.Windows.Data.ListCollectionView.ProcessCollectionChangedWithAdjustedIndex(NotifyCollectionChangedEventArgs args, Int32 adjustedOldIndex, Int32 adjustedNewIndex)
   at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.RemoveItem(Int32 index)
   at System.Collections.ObjectModel.Collection`1.Remove(T item)
   at Tennotech.Hilding.Watchman.Utilities.MirroredRadList`2.SourceCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e) in C:\BuildAgent\work\a6c0493e3d7aa6b\Source\Tennotech.Hilding.Watchman.Utilities\MirroredRadList.cs:line 193
   at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Telerik.Windows.Data.ObservableItemCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.RemoveItem(Int32 index)
   at System.Collections.ObjectModel.Collection`1.Remove(T item)
   at Tennotech.Hilding.Watchman.Framework.Devices.GenericRecordingsSynchronizer.OnRecordingsUpdated(Object sender, ParameterizedEventArgs`1 eventArgs) in C:\BuildAgent\work\a6c0493e3d7aa6b\Source\Tennotech.Hilding.Watchman.Framework\Devices\GenericRecordingsSynchronizer.cs:line 174
   at System.Reactive.AnonymousSafeObserver`1.OnNext(T value)
   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)

[Ola]

An update to the issue:

The ObservableCollection to which the item is added is part of a CompositeObservable, to which the ItemsSource of a RadTimeline is bound. The issue seems to be related Windows 7, we get the exception almost every time a new item is added. We think we have seen the issue on window 10 as well, but can not confirm it today.

[Ola]

I mean CompositeCollection, not CompositeObservable.

[Martin Ivanov]

Hello Ola,

I cannot classify this exception as a general issue in UI for WPF, but as a common exception in .NET. Mostly this happens when you try to reach an element in a collection by its index and the index is equal or bigger than the collection count.

About the specific scenario, I without your implementation I cannot tell what happens, and this is why I would ask you to send me some runnable code snippets here that demonstrates the exception. Alternatively, you can create a new project showing the issue and send it via the support ticketing system.

Regards,
Martin Ivanov
Progress Telerik

[Ola]

We have concluded that this only happens on Windows 7, and now our only customer with Windows 7 have upgraded to Windows 10, so from our perspective this has been resolved. We will never try running the RadTimline on Windows 7 again. :)

/Ola