NullReferenceException

[Mark]

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=Telerik.Windows.Data
  StackTrace:
       at Telerik.Windows.Data.DataItemCollection.<SetItemsSource>b__3(NotifyCollectionChangedEventArgs c) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\DataItemCollection.cs:line 721
       at Telerik.Windows.Data.DataItemCollection.<>c__DisplayClass18.<BindCollections>b__15(NotifyCollectionChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\DataItemCollection.cs:line 838
       at Telerik.Windows.Data.ObservableCollectionManager.HandleCollectionChanged(IList sender, NotifyCollectionChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\Synchronization\ObservableCollectionManager.cs:line 97
       at Telerik.Windows.Data.ObservableCollectionManager.Telerik.Windows.Data.IWeakEventListener<System.Collections.Specialized.NotifyCollectionChangedEventArgs>.ReceiveWeakEvent(Object sender, NotifyCollectionChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\Synchronization\ObservableCollectionManager.cs:line 86
       at Telerik.Windows.Data.WeakEvent.WeakListener`1.Handler(Object sender, TArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\WeakEvents\WeakEvent.cs:line 33
       at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
       at System.ComponentModel.SortDescriptionCollection.OnCollectionChanged(NotifyCollectionChangedAction action)
       at System.ComponentModel.SortDescriptionCollection.ClearItems()
       at System.Collections.ObjectModel.Collection`1.Clear()
       at Telerik.Windows.Data.CollectionHelper.Reset(IEnumerable source, IList target, Func`2 itemConverter) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\CollectionHelper.cs:line 437
       at Telerik.Windows.Data.CollectionHelper.Reset(IEnumerable source, IList target) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\CollectionHelper.cs:line 420
       at Telerik.Windows.Data.ObservableCollectionManager.HandleCollectionChanged(IList sender, NotifyCollectionChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\Synchronization\ObservableCollectionManager.cs:line 119
       at Telerik.Windows.Data.ObservableCollectionManager.Telerik.Windows.Data.IWeakEventListener<System.Collections.Specialized.NotifyCollectionChangedEventArgs>.ReceiveWeakEvent(Object sender, NotifyCollectionChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\Synchronization\ObservableCollectionManager.cs:line 86
       at Telerik.Windows.Data.WeakEvent.WeakListener`1.Handler(Object sender, TArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\WeakEvents\WeakEvent.cs:line 33
       at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
       at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
       at Telerik.Windows.Data.RadObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\RadObservableCollection.cs:line 149
       at Telerik.Windows.Data.ObservableItemCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\ObservableItemCollection.cs:line 91
       at System.Collections.ObjectModel.ObservableCollection`1.ClearItems()
       at Telerik.Windows.Data.RadObservableCollection`1.ClearItems() in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\RadObservableCollection.cs:line 240
       at Telerik.Windows.Data.ObservableItemCollection`1.ClearItems() in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\ObservableItemCollection.cs:line 82
       at System.Collections.ObjectModel.Collection`1.Clear()
       at Telerik.Windows.Data.DataItemCollection.ClearLocalDescriptors() in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\DataItemCollection.cs:line 165
       at Telerik.Windows.Data.DataItemCollection.set_CollectionView(QueryableCollectionView value) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\DataItemCollection.cs:line 97
       at Telerik.Windows.Data.DataItemCollection.ClearItemsSource() in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\Collections\DataItemCollection.cs:line 937
       at Telerik.Windows.Controls.GridView.GridViewDataControl.<>c__DisplayClass18.<Bind>b__17() in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\GridView\GridView\GridView\GridViewDataControl.cs:line 3644
       at Telerik.Windows.Controls.CursorManager.PerformTimeConsumingOperation(FrameworkElement frameworkElement, Action action) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Controls\CursorManager.cs:line 16
       at Telerik.Windows.Controls.GridView.GridViewDataControl.Bind(Object newValue) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\GridView\GridView\GridView\GridViewDataControl.cs:line 3620
       at Telerik.Windows.Controls.GridView.GridViewDataControl.OnItemsSourceChanged(Object oldValue, Object newValue) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\GridView\GridView\GridView\GridViewDataControl.cs:line 3274
       at Telerik.Windows.Controls.DataControl.OnItemsSourcePropertyChanged(DependencyObject origin, DependencyPropertyChangedEventArgs args) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Core\Data\DataControl.cs:line 143
       at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
       at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
       at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
       at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
       at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp)
       at System.Windows.Data.BindingExpressionBase.Invalidate(Boolean isASubPropertyChange)
       at System.Windows.Data.BindingExpression.TransferValue(Object newValue, Boolean isASubPropertyChange)
       at System.Windows.Data.BindingExpression.Activate(Object item)
       at System.Windows.Data.BindingExpression.OnDataContextChanged(DependencyObject contextElement)
       at System.Windows.Data.BindingExpression.HandlePropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
       at System.Windows.Data.BindingExpressionBase.OnPropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
       at System.Windows.Data.BindingExpression.OnPropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
       at System.Windows.DependentList.InvalidateDependents(DependencyObject source, DependencyPropertyChangedEventArgs sourceArgs)
       at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
       at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
       at System.Windows.TreeWalkHelper.InvalidateTreeDependentProperty(TreeChangeInfo info, DependencyObject d, FrameworkObject& fo, DependencyProperty dp, FrameworkPropertyMetadata fMetadata, Style selfStyle, Style selfThemeStyle, ChildRecord& childRecord, Boolean isChildRecordValid, Boolean hasStyleChanged, Boolean isSelfInheritanceParent)
       at System.Windows.TreeWalkHelper.InvalidateTreeDependentProperties(TreeChangeInfo info, FrameworkElement fe, FrameworkContentElement fce, Style selfStyle, Style selfThemeStyle, ChildRecord& childRecord, Boolean isChildRecordValid, Boolean hasStyleChanged, Boolean isSelfInheritanceParent)
       at System.Windows.FrameworkElement.InvalidateTreeDependentProperties(TreeChangeInfo parentTreeState, Boolean isSelfInheritanceParent)
       at System.Windows.FrameworkElement.OnAncestorChangedInternal(TreeChangeInfo parentTreeState)
       at System.Windows.TreeWalkHelper.OnAncestorChanged(DependencyObject d, TreeChangeInfo info)
       at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
       at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
       at System.Windows.DescendentsWalker`1.VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
       at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
       at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
       at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
       at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
       at System.Windows.DescendentsWalker`1.VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
       at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
       at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
       at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
       at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
       at System.Windows.DescendentsWalker`1.VisitNode(DependencyObject d)
       at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
       at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
       at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
       at System.Windows.DescendentsWalker`1.StartWalk(DependencyObject startNode, Boolean skipStartNode)
       at MS.Internal.PrePostDescendentsWalker`1.StartWalk(DependencyObject startNode, Boolean skipStartNode)
       at System.Windows.TreeWalkHelper.InvalidateOnTreeChange(FrameworkElement fe, FrameworkContentElement fce, DependencyObject parent, Boolean isAddOperation)
       at System.Windows.FrameworkElement.OnVisualParentChanged(DependencyObject oldParent)
       at System.Windows.Media.Visual.FireOnVisualParentChanged(DependencyObject oldParent)
       at System.Windows.Media.Visual.RemoveVisualChild(Visual child)
       at System.Windows.FrameworkElement.set_TemplateChild(UIElement value)
       at System.Windows.StyleHelper.ClearGeneratedSubTree(HybridDictionary[] instanceData, FrameworkElement feContainer, FrameworkContentElement fceContainer, FrameworkTemplate oldFrameworkTemplate)
       at System.Windows.StyleHelper.DoTemplateInvalidations(FrameworkElement feContainer, FrameworkTemplate oldFrameworkTemplate)
       at System.Windows.Controls.ContentPresenter.OnTemplateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
       at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
       at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
       at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
       at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
       at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
       at System.Windows.Controls.ContentPresenter.EnsureTemplate()
       at System.Windows.Controls.ContentPresenter.OnPreApplyTemplate()
       at System.Windows.FrameworkElement.ApplyTemplate()
       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.InvokeOnRenderCallback.DoWork()
       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 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.Window.ShowHelper(Object booleanBox)
       at System.Windows.Window.Show()
       at System.Windows.Window.ShowDialog()
  InnerException:

[Mark]

i have dialog

<Border Grid.Column="0" Grid.Row="0" BorderThickness="1" BorderBrush="Black">
            <telerik:RadTreeView Name="NavigationTreeView" ItemsSource="{Binding Path=ChildrenView}"
                      SelectedItem="{Binding Path=ActiveItem, Mode=TwoWay}"
                      Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">

                <telerik:RadTreeView.ItemTemplate>
                    <HierarchicalDataTemplate ItemsSource="{Binding Path=ChildrenView}">
                        <TextBlock FontWeight="Regular" Text="{Binding Path=Name, Converter={StaticResource StubConverter}}" />
                    </HierarchicalDataTemplate>
                </telerik:RadTreeView.ItemTemplate>
            </telerik:RadTreeView>
        </Border>

        <ScrollViewer Grid.Column="1" Grid.Row="0" Margin="10,0,0,0" HorizontalScrollBarVisibility="Disabled"  VerticalScrollBarVisibility="Auto">
            <ContentControl Content="{Binding Path=ActiveItem}">
                <ContentControl.Resources>
                    <DataTemplate DataType="{x:Type local:GeneralOptionsViewModel}">
                        <local:GeneralOptionsPanel/>
                    </DataTemplate>
                    <DataTemplate DataType="{x:Type map:MapOptionsViewModel}">
                        <map:MapOptionsPanel/>
                    </DataTemplate>
                    <DataTemplate DataType="{x:Type map:RegionOptionsViewModel}">
                        <map:RegionOptionsPanel/>
                    </DataTemplate>
                </ContentControl.Resources>
            </ContentControl>
        </ScrollViewer>

Following user control (raddridview in it) used in data template crush application when user click other node other than MapOptionsPanel

<UserControl x:Class="AppLication.MapOptionsPanel"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:dls="http://www.digitallivingsoftware.com/Presentation"
             xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
             xmlns:local="clr-namespace:Modular.MapView.Implementation"
             mc:Ignorable="d"
             d:DesignHeight="300" d:DesignWidth="300">
    <DockPanel>

        <Grid DockPanel.Dock="Left">
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>

            <!-- THIS GRID RAISE EXCEPTION WHEN USER CLICK OTHER ITEM IN TREEE -->
            <telerik:RadGridView Grid.Row="0" Name="AssetGridView"
                             ItemsSource="{Binding Path=ChildrenView}" SelectedItem="{Binding Path=Children.Selected}"
                             AutoGenerateColumns="False" CanUserDeleteRows="True" CanUserInsertRows="False" SelectionMode="Single"
                             IsFilteringAllowed="False" CanUserFreezeColumns="False" RowIndicatorVisibility="Collapsed"
                             ShowGroupPanel="False" IsReadOnly="True">
                <telerik:RadGridView.Columns>
                    <telerik:GridViewMaskedTextBoxColumn Header="Name" DataMemberBinding="{Binding Path=Name}" Width="*" MaxWidth="300"/>
                    <telerik:GridViewMaskedTextBoxColumn Header="North West X" DataMemberBinding="{Binding Path=NorthWestX}" Width="75"/>
                    <telerik:GridViewMaskedTextBoxColumn Header="North West Y" DataMemberBinding="{Binding Path=NorthWestY}" Width="75"/>
                    <telerik:GridViewMaskedTextBoxColumn Header="South East X" DataMemberBinding="{Binding Path=SouthEastX}" Width="75"/>
                    <telerik:GridViewMaskedTextBoxColumn Header="South East Y" DataMemberBinding="{Binding Path=SouthEastY}" Width="75"/>
                </telerik:RadGridView.Columns>
            </telerik:RadGridView>

            <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Left">
                <Button Content="Add" Margin="5,5,5,0" Command="{Binding AddNewChildCommand}" IsEnabled="{Binding CanAddNewChild}" Width="75" />
                <Button Content="Delete" Margin="0,5,5,0" Command="{Binding RemoveChildCommand}" IsEnabled="{Binding CanRemoveChild}" Width="75" />
            </StackPanel>
        </Grid>

    </DockPanel>
</UserControl>

[Vlad]

Hi,

 Can you post the grid version?

Best wishes,
Vlad
the Telerik team

[Mark]

I have v2.0.50727

[Vlad]

Hi,

 I'm afraid that this is not the grid assembly version.

All the best,
Vlad
the Telerik team

[Mark]

Sorry, it is 2011.2.920.35

[Vlad]

Hi,

 Please open support ticket and send us an example project where we can reproduce the exception. 

Kind regards,
Vlad
the Telerik team

[Vera]

Hello Mark,

I have tested your scenario with our Q3 2011 version and this exception is no longer reproducible.

All the best,
Vera
the Telerik team