System.NullReferenceException: Object reference not set to an instance of an object

[Ali]

Dear experts,

I am having this Exception randomly in my WPF application, any idea how to fix it? I occurs randomly when I try to add a source data file on my application:

12/06/2017 02:37:28 PM Fatal: App :: Unhandled Exception!
Machine Name : .....User Name :.......  
Exception : System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.RealizeRows(Int32 startIndex, Int32 endIndex, Double& verticalOffset, HashSet`1& realizedRows) at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.MeasureOverride(Size availableSize) at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.ContextLayoutManager.UpdateLayout() at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg) at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks() at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget) at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget) 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)

12/06/2017 02:57:02 PM Fatal: App :: Unhandled Exception!
Machine Name : ......User Name : ......
Exception : System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.RealizeRows(Int32 startIndex, Int32 endIndex, Double& verticalOffset, HashSet`1& realizedRows) at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.MeasureOverride(Size availableSize) at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint) at Telerik.Windows.Controls.GridView.GridViewScrollViewer.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Border.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.DockPanel.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Border.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at Telerik.Windows.Controls.GridView.GridViewDataControl.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Border.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Border.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Border.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Documents.AdornerDecorator.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Control.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Documents.AdornerDecorator.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Controls.Grid.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.Window.MeasureOverrideHelper(Size constraint) at System.Windows.Window.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.ContextLayoutManager.UpdateLayout() at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg) at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks() at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget) at System.Windows.Media.MediaContext.AnimatedRenderMessageHandler(Object resizedCompositionTarget) 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)

[Ali]

I am getting this Exception randomly in my WPF application, any idea how to fix it?
It occurs randomly when I try to add a source data file on my application.
I have debugged my application and didn't find any NULL value so far, but still above Exception is occurring randomly
Either when I add a new source or it also happens when I "refresh" the data form. 

[Ali]

Screen Shot

[Martin Ivanov]

Hello Ali,

We are not sure why the issue appears on your side, but we are aware for a bug with similar symptoms. We are investigating a possible solution for it which might be available in our next LIB. You can check the new LIB next Monday or Tuesday and see if the issue still reproduces.

Regards,
Martin Ivanov
Progress Telerik

[Ali]

Hi Martin,

Thanks for your quick feedback. I will wait for your next LIB. Meanwhile if you can suggest any other alternative and can you please also mention here (bug details) you investigating? It will be helpful.

Best Regards

 

[Ivan Ivanov]

Hello,

The similar issue that can be related to the one that you are reporting involves the usage of heavy DataTemplates (set to CellTemplate) and sorting. Currently we do not have a workaround for it. We managed to add the fix in today's LIB so that you can test it on your side as soon as it is available for download.

Regards,
Ivan Ivanov
Progress Telerik

[Peter]

I am getting the same thing using version 2018.2.620.45

But when I change anything even remove a blank line and recompile the program the error disappears. But when I close and reopen the project the error is back.

[Vladimir Stoyanov]

Hello Peter,

May I ask you to isolate this behavior in a sample project and send it to us in a new support ticket? Additionally you can provide some steps which we can follow in order to replicate the exception. This way we will be able to investigate it our side.

Thank you in advance for any help you can provide.

Regards,
Vladimir Stoyanov
Progress Telerik