WPF DataGrid EnableColumnVirtualization="True" Raises NullReferenceException at DataGridCellsPanel.get_HasCorrectRealizedColumns()

wpf, wpf-4.0, wpfdatagrid

Solution

I was able to get to it going by changing the `VirtualizationMode` from Recycling to Standard.

    <DataGrid ItemsSource="{Binding Items}" 
     AutoGenerateColumns="True"
     EnableColumnVirtualization="True"
     Standard.VirtualizingStackPanel.IsVirtualizing="True"
     VirtualizingStackPanel.VirtualizationMode="Standard">

I'd still like to know why Recycling doesn't work ... bug?

Hope this helps anyone that runs into the same problem.

Problem

I have a WPF DataGrid with`EnableColumnVirtualization="True"`. The user control displays but as soon as you scroll or resize you'll receive a `NullReferenceException` at `DataGridCellsPanel.get_HasCorrectRealizedColumns()`. Setting `ColumnVirtualization="False"` corrects the issue. I've tried removing `EnableRowVirtualization="True"` ... etc thinking that maybe it was due to a combination of properties but I'm able to reproduce the issue with a very simple DataGrid: ``` <DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="True" EnableColumnVirtualization="True" ``` Has anyone else run into this? I'm running Win7 64. Thanks all! ``` at System.Windows.Controls.DataGridCellsPanel.get_HasCorrectRealizedColumns() at System.Windows.Controls.Primitives.DataGridCellsPresenter.SyncProperties(Boolean forcePrepareCells) at System.Windows.Controls.DataGridRow.SyncProperties(Boolean forcePrepareCells) at System.Windows.Controls.DataGridRow.PrepareRow(Object item, DataGrid owningDataGrid) at System.Windows.Controls.DataGrid.PrepareContainerForItemOverride(DependencyObject element, Object item) at System.Windows.Controls.ItemsControl.MS.Internal.Controls.IGeneratorHost.PrepareItemContainer(DependencyObject container, Object item) at System.Windows.Controls.VirtualizingStackPanel.InsertContainer(Int32 childIndex, UIElement container, Boolean isRecycled) at System.Windows.Controls.VirtualizingStackPanel.AddContainerFromGenerator(Int32 childIndex, UIElement child, Boolean newlyRealized, Boolean isBeforeViewport) at System.Windows.Controls.VirtualizingStackPanel.MeasureChild(IItemContainerGenerator& generator, IContainItemStorage& itemStorageProvider, IContainItemStorage& parentItemStorageProvider, Object& parentItem, Boolean& hasUniformOrAverageContainerSizeBeenSet, Double& computedUniformOrAverageContainerSize, Boolean& computedAreContainersUniformlySized, IList& items, Object& item, IList& children, Int32& childIndex, Boolean& visualOrderChanged, Boolean& isHorizontal, Size& childConstraint, Rect& viewport, VirtualizationCacheLength& cacheSize, VirtualizationCacheLengthUnit& cacheUnit, Boolean& foundFirstItemInViewport, Double& firstItemInViewportOffset, Size& stackPixelSize, Size& stackPixelSizeInViewport, Size& stackPixelSizeInCacheBeforeViewport, Size& stackPixelSizeInCacheAfterViewport, Size& stackLogicalSize, Size& stackLogicalSizeInViewport, Size& stackLogicalSizeInCacheBeforeViewport, Size& stackLogicalSizeInCacheAfterViewport, Boolean& mustDisableVirtualization, Boolean isBeforeFirstItem, Boolean isAfterFirstItem, Boolean isAfterLastItem, Boolean skipActualMeasure, Boolean skipGeneration, Boolean& hasBringIntoViewContainerBeenMeasured, Boolean& hasVirtualizingChildren) at System.Windows.Controls.VirtualizingStackPanel.MeasureOverrideImpl(Size constraint, Nullable`1& lastPageSafeOffset, List`1& previouslyMeasuredOffsets, Boolean remeasure) at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint) at System.Windows.Controls.Primitives.DataGridRowsPresenter.MeasureOverride(Size constraint) at System.Windows.FrameworkElement.MeasureCore(Size availableSize) at System.Windows.UIElement.Measure(Size availableSize) at System.Windows.ContextLayoutManager.UpdateLayout() at System.Windows.Controls.VirtualizingStackPanel.<>c__DisplayClassa.<InitializeViewport>b__7() 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.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 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.LegacyInvokeImpl(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.Application.RunInternal(Window window) at System.Windows.Application.Run() at ....App.Main() in c:\....\obj\Debug\App.g.cs:line 0 ```

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