Use Popup in EditingTemplateCell: Message=Value cannot be null. Parameter name:descendant

Question

I'm using a WPF DataGrid and I put a DataGridTemplateColumn. Because the column should perform edit on a complex type (it's an object), I decided to put a togglebutton that open a popup. The code is the follow:

                <DataTemplate>
                    <Grid>
                        <ToggleButton Grid.Column="2" x:Name="tb" Focusable="false" IsChecked="False" ClickMode="Press"  Content="Edit values" />
                        <Popup IsOpen="{Binding ElementName=tb, Path=IsChecked, Mode=OneWay}" Placement="Bottom" x:Name="Popup" Focusable="False" StaysOpen="False" AllowsTransparency="True"  Margin="0,1,0,0">
                            <Grid x:Name="dd" SnapsToDevicePixels="True">
                                <Border x:Name="ddb" Margin="0,-1,0,0" BorderBrush="DarkGray"  BorderThickness="1" CornerRadius="0,0,3,3" Background="Gray">
                                    <Grid>
                                    <Grid.RowDefinitions>
                                        <RowDefinition />
                                        <RowDefinition />
                                        <RowDefinition />
                                    </Grid.RowDefinitions>
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition />
                                        <ColumnDefinition />
                                    </Grid.ColumnDefinitions>
                                    <TextBlock Text="Uno:" Grid.Row="0" Grid.Column="0" />
                                    <TextBox Text="{Binding Path=calendar.uno, Mode=TwoWay, StringFormat={}{0:0.##}}" Grid.Row="0" Grid.Column="1" />
                                    <TextBlock Text="Due:" Grid.Row="1" Grid.Column="0" />
                                        <TextBox Text="{Binding Path=calendar.due, Mode=TwoWay, StringFormat={}{0:0.##}}" Grid.Row="1" Grid.Column="1" />
                                    <TextBlock Text="Tre:" Grid.Row="2" Grid.Column="0" />
                                        <TextBox Text="{Binding Path=calendar.tre, Mode=TwoWay, StringFormat={}{0:0.##}}" Grid.Row="2" Grid.Column="1" />
                                    </Grid>
                                </Border>
                            </Grid>
                        </Popup>
                    </Grid>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>

The popup works, but often the following exception occurs:

System.ArgumentNullException was unhandled
  Message=Value cannot be null.
Parameter name: descendant
  Source=PresentationCore
  ParamName=descendant
  StackTrace:
       at System.Windows.Media.VisualTreeHelper.IsAncestorOf(DependencyObject ancestor, DependencyObject descendant, Type stopType)
       at System.Windows.Controls.DataGridCell.RemoveBindingExpressions(BindingGroup bindingGroup, DependencyObject element)
       at System.Windows.Controls.DataGridCell.BuildVisualTree()
       at System.Windows.Controls.DataGridCell.OnIsEditingChanged(Boolean isEditing)
       at System.Windows.Controls.DataGridCell.OnIsEditingChanged(Object sender, 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.DependencyObject.SetValue(DependencyProperty dp, Boolean value)
       at System.Windows.Controls.DataGridCell.BeginEdit(RoutedEventArgs e)
       at System.Windows.Controls.DataGrid.OnExecutedBeginEdit(ExecutedRoutedEventArgs e)
       at System.Windows.Controls.DataGrid.OnExecutedBeginEdit(Object sender, ExecutedRoutedEventArgs e)
       at System.Windows.Input.CommandBinding.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
       at System.Windows.Input.CommandManager.ExecuteCommandBinding(Object sender, ExecutedRoutedEventArgs e, CommandBinding commandBinding)
       at System.Windows.Input.CommandManager.FindCommandBinding(CommandBindingCollection commandBindings, Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
       at System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
       at System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
       at System.Windows.UIElement.OnExecutedThunk(Object sender, ExecutedRoutedEventArgs e)
       at System.Windows.Input.ExecutedRoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object target)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
       at System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)
       at System.Windows.Input.RoutedCommand.Execute(Object parameter, IInputElement target)
       at System.Windows.Controls.DataGrid.BeginEdit(RoutedEventArgs editingEventArgs)
       at System.Windows.Controls.DataGridCell.OnAnyMouseLeftButtonDown(MouseButtonEventArgs e)
       at System.Windows.Controls.DataGridCell.OnAnyMouseLeftButtonDownThunk(Object sender, MouseButtonEventArgs e)
       at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
       at System.Windows.UIElement.OnMouseDownThunk(Object sender, MouseButtonEventArgs e)
       at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
       at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
       at System.Windows.Input.InputManager.ProcessStagingArea()
       at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
       at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
       at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
       at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at System.Windows.Interop.HwndSource.InputFilterMessage(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.Threading.Dispatcher.Run()
       at System.Windows.Application.RunDispatcher(Object ignore)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run(Window window)
       at System.Windows.Application.Run()
       at WpfApplication5.App.Main() in C:\Users\r.sarati\Desktop\WpfDataGridSynchronized_V1.00\WpfDataGridSynchronized\CF40\WpfApplication5\obj\Debug\App.g.cs:line 50
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(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.Threading.ThreadHelper.ThreadStart()

What's the problem? (use multiple columns is not a valid alternative)

Hi, Did you find what was causing this issue ? I have a similar exception with the same track trace. Thanks — user564029

absinth absinth · Accepted Answer · 2012-08-08T16:31:56

currently I have this exception in my app too; same stack trace. I found also few solutions for this but these solutions are not very "nice":

1 I used aero style for whole dialog where I have DataGrid to have same look for default controls in different Windows versions (mainly for XP to look controls "nicer"). When I comment following part of code in xaml of dialog no other exception is showing:

<ResourceDictionary.MergedDictionaries>
       <ResourceDictionary Source="/PresentationFramework.Aero, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />
</ResourceDictionary.MergedDictionaries>

But I'm on XP now, I must check if this problem is solved also on Win7. EDIT: works also for Windows7.

2 Try check this link on microsoft page: http://support.microsoft.com/kb/2498911

3 As it is written also on microsoft page you can still turn off Virtualization for Row or Column of your datagrid but if you have for example 1000 rows it takes some time to load everything :/

EDIT :

4. I downloaded the Aero.NormalColor.xaml (part of themes from microsoft available here: http://msdn.microsoft.com/en-us/library/aa970773.aspx) and add this theme to my app.xaml to app dictionary. It seems that this fixed the problem (probably same look but some differencies in code for this themes).

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Themes/GlassButton.xaml"/>
            <ResourceDictionary Source="Themes/Aero.NormalColor.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

Use Popup in EditingTemplateCell: Message=Value cannot be null. Parameter name:descendant

1 Answers