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Error on mouse up after re-styling GridViewItemsControl

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Will asked on 19 Jun 2008, 03:59 PM

Hi,

After restyling the grid view items control to take out the group panel I get an error when clicking on cells:

    
            {System.ArgumentNullException: Value cannot be null. 
        
            Parameter name: reference 
        
               at System.Windows.Media.VisualTreeHelper.GetDescendantBounds(Visual reference) 
        
               at Telerik.Windows.Controls.UI.DragDropManager.IsMouseOverTarget(Visual target, GetPositionDelegate getPosition) 
        
               at Telerik.Windows.Controls.UI.GridViewItemsControl.OnPreviewMouseUp(MouseButtonEventArgs e) 
        
               at System.Windows.UIElement.OnPreviewMouseUpThunk(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.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)

My control template is as follows:

    
             <ControlTemplate x:Key="GridViewItemsControlTableTemplate" TargetType="{x:Type UI:GridViewItemsControl}"> 
        
                <Grid Background="{TemplateBinding Background}"> 
        
                    <Grid.Resources> 
        
                            <UI:DoubleToGridLengthConverter x:Key="DoubleToGridLengthConverter" /> 
        
                    </Grid.Resources> 
        
                        <Grid.RowDefinitions> 
        
                            <RowDefinition Height="Auto" /> 
        
                            <RowDefinition /> 
        
                            <RowDefinition x:Name="ScrollBarRow" MinHeight="10"  
        
                                           Height="{Binding Source={StaticResource {x:Static SystemParameters.HorizontalScrollBarHeightKey}},  
        
                                Converter={StaticResource DoubleToGridLengthConverter}}"/> 
        
                        </Grid.RowDefinitions> 
        
                        <Grid.ColumnDefinitions> 
        
                            <ColumnDefinition /> 
        
                            <ColumnDefinition x:Name="ScrollBarColumn" MinWidth="10" Width="{Binding Source={StaticResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}, Converter={StaticResource DoubleToGridLengthConverter}}"/> 
        
                        </Grid.ColumnDefinitions> 
        
                        <UI:GridViewBackground x:Name="PART_GridViewBackground" Margin="10,0,0,0" Grid.Row="0"  
        
                                               Grid.ColumnSpan="1" Grid.RowSpan="2"  
        
                                               HorizontalAlignment="Stretch" VerticalAlignment="Stretch" IsHitTestVisible="False"/> 
        
                        <StackPanel Grid.Row="0"> 
        
                            <Border Margin="0,0,0,0" BorderThickness="0" ClipToBounds="True" 
        
                                    Background="{StaticResource {x:Static Resources:FunctionalBrushes.EntityTabBackgroundBrushKey}}"> 
        
                                <UI:GridViewHeaderRow Name="PART_HeaderRow" VerticalAlignment="Top"/> 
        
                            </Border> 
        
                            <UI:GridViewNewRow Name="PART_AddNewRow" Margin="10,0,0,0"  
        
                                               VerticalAlignment="Bottom" HorizontalAlignment="Stretch"  
        
                                               Visibility="Collapsed" /> 
        
                        </StackPanel> 
        
                        <ScrollViewer Name="PART_ItemsScrollViewer" Focusable="False" VerticalScrollBarVisibility="Auto"  
        
                                      HorizontalScrollBarVisibility="Auto"  
        
                                      CanContentScroll="True" Grid.Row="1" Grid.RowSpan="2" Grid.ColumnSpan="2"> 
        
                            <ItemsPresenter Margin="10, 0, 0, 0"/> 
        
                        </ScrollViewer> 
        
                    </Grid> 
        
                    <ControlTemplate.Triggers>           
        
                        <Trigger Property="ComputedVerticalScrollBarVisibility" SourceName="PART_ItemsScrollViewer" Value="Collapsed"> 
        
                            <Setter Property="Width" TargetName="ScrollBarColumn" Value="10" /> 
        
                        </Trigger> 
        
                        <Trigger Property="ComputedHorizontalScrollBarVisibility" SourceName="PART_ItemsScrollViewer" Value="Collapsed"> 
        
                            <Setter Property="Height" TargetName="ScrollBarRow" Value="10" /> 
        
                        </Trigger> 
        
                    </ControlTemplate.Triggers> 
        
                </ControlTemplate>

Have I done something wrong or is this a bug?

Kind regards,

Will Holley

2 Answers, 1 is accepted

answered on 20 Jun 2008, 11:26 AM

Hi Will,

I managed to reproduce the error. It is caused by a bug in the control -- the code "assumes" the group panel is always present. We have reworked the drag/drop grouping code and the bug does not appear in our latest dev builds.

We are working on publishing a second beta build release at the end of next week that will have that and the rest of the issues you reported fixed. In addition we will have a public property that will allow you to hide the group panel, so that you won't have to define the control template yourself.

Greetings,
Hristo Deshev
the Telerik team

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