Unfortunately I'm not able to reproduce this issue by myself. That's why I don't have any sample project for this. But I receive this exception from our production environment (~50 users) at least once a week. If I was able to reproduce that I would isolate the cause. But I have no idea what cause the issue exactly.

Is it possible to turn on some kind of logging for infragistics components? My guess is that user works with XamDataGrid or DockManager. If we knew what exactly is happening inside these components it would help us.

So

1) There was an exception that was thrown from Infragistics code.

2) This is kind of code customer can't control anyhow. I did not call anything to get this exception. Your internal timer was fired and it tried to get access to your internal weak list on the wrong index.

3) That happens very-very rare

And you are saying that I have to provide you a sample that allows you to reproduce that before you will start looking into that, right? So in you opinion I have to decompile your code, find out how this issue is possible, create a sample that reproduces the issue using your public API only and then you will start looking into that. It seems Infragistics provides very nice support.

By the way, could you please explain is it safe to handle this exception in dispatcher exception handler and ignore it? Will your components operate correct after that? Or I have to restart application anyway?

Sorry guys, my post above is actually about another exception from your code. I thought I reported that too. Here it is:

ystem.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
at System.ThrowHelper.ThrowArgumentOutOfRangeException()
at Infragistics.Collections.WeakList`1.GetItemHelper(Int32 index)
at Infragistics.Windows.Internal.ThrottleTimer.OnTimerTick_Sync()
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
at System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Delegate.DynamicInvokeImpl(Object[] args)
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)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(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)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)

Also I'd like to understand can I expect this to be fixed in recent releses? 

Hello,

Since this is not a known issue, we are not able to reproduce this beahavior and if you send us an isolated sample project, where this is reproduced we will be glad to assist you further with this.

Looking forward for your reply.

I'm working on huge application that includes dozen of different views, DockManager, DataGrid, DataTree, Tiles and a bunch of simple editors all from Infragistics. I can't share this application with you because I'm not allowed to publish it according to my job contract. Even I was allowed, this application would not run on your side, because it is bounded to a very specific environment.

It is a huge work to create any kind of sample project that emulates original application as is. Also even if we had had such project it would have taken inappropriate amount of time to reproduce the issue. I have 20 users working with application every single day for 8 hours and I have automated reporting system, that notifies me when something bad happens. Under these circumstances I get like 2 incidents we are talking about in a month. How long do you think it may take to reproduce that in sample project on your side?

What I can see in exceptions that I posted is that first was is occured while element was adding to xamDataTree and another one was occured while some timer was fired. But both of them are week references related. One hint I may offer you is that I'm using different Infragistincs components on different threads. I mean I have one application window on one thread and another one on another thread. Actually I have 3 different UI threads in my appication. All of them are in the same domain. And any of thme has Infragistics controls. If you are sharing some kind data between different components it could be related.

Thanks Stefan

As I mentioned before, I have 3 UI threads. One of them is main thread and there are no xamDataTrees on this thread. However both of two remaining threads use XamDataTree and one of these threads can have multiple instances of xamDataTree. As far as I can see drag'n'drop is not enabled in both cases. At least can't drag anything out of the Tree or drop anything there. Basically both trees just show binded data and allow user to select an item within a tree.

This is first tree setup in xaml:

<ig:XamDataTree x:Name="algoDataTree"
HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
ItemsSource="{Binding Path=Algos}" BorderThickness="0">

<ig:XamDataTree.CheckBoxSettings>
<ig:CheckBoxSettings CheckBoxVisibility="Visible"/>
</ig:XamDataTree.CheckBoxSettings>

<ig:XamDataTree.GlobalNodeLayouts>
<ig:NodeLayout Key="AlgoLayout" TargetTypeName="AlgoViewModel"
CheckBoxMemberPath="IsChecked"
IsExpandedMemberPath="IsExpanded"
DisplayMemberPath="DisplayName"/>

<ig:NodeLayout Key="AlgoInstanceLayout" TargetTypeName="AlgoInstanceViewModel"
CheckBoxMemberPath="IsChecked"
DisplayMemberPath="DisplayName"/>

</ig:XamDataTree.GlobalNodeLayouts>
</ig:XamDataTree>

And this is another one:

<ig:XamDataTree
x:Name="algosTree"
Grid.Row="0"
Grid.Column="0"
ItemsSource="{Binding Path=AlgoPositionCountersViewModel.Algos}"
SelectedNodesCollectionChanged="algoDataTree_SelectedNodesCollectionChanged"
BorderThickness="1" Margin="0,0,2,0">

<ig:XamDataTree.GlobalNodeLayouts>

<ig:NodeLayout
Key="AlgoLayout"
TargetTypeName="AlgoInstanceWithPositionsViewModel"
IsExpandedMemberPath="IsExpanded"
DisplayMemberPath="DisplayName" />

<ig:NodeLayout
Key="PositionLayout"
TargetTypeName="PositionViewModel"
DisplayMemberPath="DisplayName"/>

</ig:XamDataTree.GlobalNodeLayouts>
</ig:XamDataTree>

Hello,

I have forwarded your issue to our engineering team and after some investigation they conclude that this seems to be caused by the Drag & Drop Framework used in the XamDataTree, but they need more details about your scenario. Could you please give us more details about your scenario where you use the XamDataTree and tell us if you show XamDataTree on window running on another thread?

Looking forward for your reply.