SilverLight Application - Error using RadExpander inside a listbox - silverlight

Question

I need your help since I get the following message in my Silverlight application:
{System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentException: Value does not fall within the expected range.
à MS.Internal.XcpImports.CheckHResult(UInt32 hr)
à MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, DependencyObject doh)
à MS.Internal.XcpImports.SetValue(IManagedPeerBase doh, DependencyProperty property, Object obj)
à System.Windows.DependencyObject.SetObjectValueToCore(DependencyProperty dp, Object value)
à System.Windows.DependencyObject.SetEffectiveValue(DependencyProperty property, EffectiveValueEntry& newEntry, Object newValue)
à System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
à System.Windows.DependencyObject.RefreshExpression(DependencyProperty dp)
à System.Windows.Data.BindingExpression.SendDataToTarget()
à System.Windows.Data.BindingExpression.SourceAcquired()
à System.Windows.Data.Debugging.BindingBreakPoint.<>c__DisplayClass4.<BreakOnSharedType>b__3()
--- Fin de la trace de la pile d'exception interne ---
à System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
à System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
à System.Delegate.DynamicInvokeImpl(Object[] args)
à System.Delegate.DynamicInvoke(Object[] args)
à StylesBudgetxaml.BindingOperation(Object BindingState, Int32 , Action )}
I’m using a listbox where I’ve changed the items into Telerik RadExpanders.
<ListBox ItemsSource="{Binding FaqItems, ElementName=Root}" ItemTemplate="{StaticResource FAQListBoxItems}" ItemContainerStyle="{StaticResource FAQListBoxItemStyle}" Width="650" ScrollViewer.HorizontalScrollBarVisibility="Disabled"/>
<ControlTemplate x:Key="ExpanderTemplate" TargetType="telerik:RadExpander">
<Grid HorizontalAlignment="{TemplateBinding HorizontalAlignment}" VerticalAlignment="{TemplateBinding VerticalAlignment}">
[...]Animation part[...]
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="{StaticResource Expander_BorderRadius}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition x:Name="col0" Width="Auto"/>
<ColumnDefinition x:Name="col1" Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition x:Name="row0" Height="Auto"/>
<RowDefinition x:Name="row1" Height="Auto"/>
</Grid.RowDefinitions>
<telerik:RadToggleButton x:Name="HeaderButton" Background="Transparent" ClickMode="{TemplateBinding ClickMode}" Foreground="{TemplateBinding Foreground}" FontWeight="{TemplateBinding FontWeight}" FontStyle="{TemplateBinding FontStyle}" FontStretch="{TemplateBinding FontStretch}" FontSize="{TemplateBinding FontSize}" FontFamily="{TemplateBinding FontFamily}" HorizontalAlignment="{TemplateBinding HorizontalHeaderAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalHeaderAlignment}" IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" TabIndex="{TemplateBinding TabIndex}" Template="{StaticResource FAQRadToggleButtonControlTemplate}" VerticalAlignment="{TemplateBinding VerticalHeaderAlignment}" VerticalContentAlignment="{TemplateBinding VerticalHeaderAlignment}">
<Grid x:Name="HeaderPanel" Background="Transparent">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Grid.Column="0" Grid.Row="0">
<Ellipse x:Name="OuterCircle" Fill="{StaticResource ControlBackground_Normal}" HorizontalAlignment="Center" Height="20" Stroke="{StaticResource ControlOuterBorder_Normal}" VerticalAlignment="Center" Width="20"/>
<Ellipse x:Name="InnerCircle" HorizontalAlignment="Center" Height="18" Stroke="{StaticResource ControlInnerBorder_Normal}" VerticalAlignment="Center" Width="18"/>
<Grid x:Name="arrowPanel" RenderTransformOrigin=".5 .5">
<Grid.RenderTransform>
<RotateTransform/>
</Grid.RenderTransform>
<Path x:Name="arrow" Data="M0,0 L0.67,0 4,2.67 7.25,0 8,0 8,0.67 4,4 0,0.75 z" Fill="{StaticResource ControlElement_Normal}" Height="4" RenderTransformOrigin="0.5,0.5" Stretch="None" Width="8">
<Path.RenderTransform>
<RotateTransform Angle="0"/>
</Path.RenderTransform>
</Path>
</Grid>
</Grid>
<telerik:LayoutTransformControl x:Name="HeaderContentTransform" Grid.Column="0" Grid.Row="0" RenderTransformOrigin=".5 .5">
<ContentPresenter x:Name="HeaderContent" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Grid.Column="1" HorizontalAlignment="Stretch" Margin="5 0" VerticalAlignment="Stretch"/>
</telerik:LayoutTransformControl>
</Grid>
</telerik:RadToggleButton>
<ContentPresenter x:Name="Content" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
</Border>
</Grid>
</ControlTemplate>
Do you know where it could come from?
Thanks in advance.

Answer 1

A few more information :
<SolidColorBrush x:Key="Expander_Background" Color="#00FFFFFF"/>
<SolidColorBrush x:Key="Expander_BorderBrush" Color="#00FFFFFF"/>
<Thickness x:Key="Expander_BorderThickness">0</Thickness>
<SolidColorBrush x:Key="ControlInnerBorder_Normal" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ControlElement_Normal" Color="#FF000000"/>
<SolidColorBrush x:Key="ControlOuterBorder_Focused" Color="#FFFFC92B"/>
<ControlTemplate x:Key="FAQRadToggleButtonControlTemplate" TargetType="telerik:RadToggleButton">
<Grid>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="FocusStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0.2" To="Focused"/>
<VisualTransition GeneratedDuration="0:0:0.2" To="Unfocused"/>
</VisualStateGroup.Transitions>
<VisualState x:Name="Unfocused"/>
<VisualState x:Name="Focused"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
</ControlTemplate>
<ControlTemplate x:Key="ToggleTemplate" TargetType="telerik:RadToggleButton">
<Grid>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="FocusStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0.2" To="Focused"/>
<VisualTransition GeneratedDuration="0:0:0.2" To="Unfocused"/>
</VisualStateGroup.Transitions>
<VisualState x:Name="Unfocused"/>
<VisualState x:Name="Focused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="0:0:0" Storyboard.TargetProperty="Visibility" Storyboard.TargetName="FocusDecorator">
<DiscreteObjectKeyFrame KeyTime="0:0:0">
<DiscreteObjectKeyFrame.Value>
<Visibility>Visible</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<ContentPresenter x:Name="Content" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
<Rectangle x:Name="FocusDecorator" IsHitTestVisible="false" Stroke="{StaticResource ControlOuterBorder_Focused}" StrokeThickness="1" StrokeDashArray="1 2" Visibility="Collapsed"/>
</Grid>
</ControlTemplate>
<CornerRadius x:Key="Expander_BorderRadius">3</CornerRadius>
<SolidColorBrush x:Key="ControlOuterBorder_Disabled" Color="#FF989898"/>
<SolidColorBrush x:Key="ControlInnerBorder_Disabled" Color="Transparent"/>
<SolidColorBrush x:Key="ControlBackground_Disabled" Color="#FFE0E0E0"/>
<SolidColorBrush x:Key="ControlElement_Disabled" Color="#FF8D8D8D"/>
<SolidColorBrush x:Key="ControlOuterBorder_MouseOver" Color="#FFFFC92B"/>
<SolidColorBrush x:Key="ControlInnerBorder_MouseOver" Color="#FFFFFFFF"/>
<LinearGradientBrush x:Key="ControlBackground_MouseOver" EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFFFFBDA" Offset="0"/>
<GradientStop Color="#FFFEEBAE" Offset="0.50"/>
<GradientStop Color="#FFFFD25A" Offset="0.50"/>
<GradientStop Color="#FFFFFBA3" Offset="1"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ControlElement_MouseOver" Color="#FF000000"/>
<LinearGradientBrush x:Key="ControlOuterBorder_Pressed" EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF282828"/>
<GradientStop Color="#FF5F5F5F" Offset="1"/>
</LinearGradientBrush>
<LinearGradientBrush x:Key="ControlInnerBorder_Pressed" EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFB69A78"/>
<GradientStop Color="#FFFFE17A" Offset="0.126"/>
</LinearGradientBrush>
<LinearGradientBrush x:Key="ControlBackground_Pressed" EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFFFDCAB" Offset="0"/>
<GradientStop Color="#FFFFD18F" Offset="0.5"/>
<GradientStop Color="#FFFE9227" Offset="0.5"/>
<GradientStop Color="#FFFFBA74" Offset="0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ControlElement_Pressed" Color="#FF000000"/>
<Style x:Key="FAQRadExpanderStyle" TargetType="telerik:RadExpander">
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
<Setter Property="VerticalContentAlignment" Value="Stretch"/>
<Setter Property="Background" Value="{StaticResource Expander_Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource Expander_BorderBrush}"/>
<Setter Property="BorderThickness" Value="{StaticResource Expander_BorderThickness}"/>
<Setter Property="Padding" Value="2"/>
<Setter Property="Template" Value="{StaticResource ExpanderTemplate}"/>
<Setter Property="telerik:AnimationManager.AnimationSelector">
<Setter.Value>
<telerik:AnimationSelector>
<telerik:ExpanderExpandCollapseAnimation AnimationName="Expand" Direction="In" TargetElementName="Content"/>
<telerik:ExpanderExpandCollapseAnimation AnimationName="Collapse" Direction="Out" TargetElementName="Content"/>
</telerik:AnimationSelector>
</Setter.Value>
</Setter>
</Style>
<DataTemplate x:Key="FAQListBoxItems">
<toolkit:WrapPanel>
<telerik:RadExpander IsExpanded="False" VerticalContentAlignment="Top"
telerik:AnimationManager.IsAnimationEnabled="{Binding ElementName=AnimationEnableCheckBox, Path=IsChecked}" Style="{StaticResource FAQRadExpanderStyle}">
<telerik:RadExpander.Header>
<ContentPresenter Margin="5" Content="{Binding Title}"/>
</telerik:RadExpander.Header>
<telerik:RadExpander.Content>
<ContentPresenter Margin="5" Content="{Binding Answer}"/>
</telerik:RadExpander.Content>
</telerik:RadExpander>
</toolkit:WrapPanel>
</DataTemplate>
<Style x:Key="FAQListBoxItemStyle" TargetType="ListBoxItem">
<Setter Property="Padding" Value="3"/>
<Setter Property="HorizontalContentAlignment" Value="Left"/>
<Setter Property="VerticalContentAlignment" Value="Top"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="TabNavigation" Value="Local"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<Grid Background="{TemplateBinding Background}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal"/>
<VisualState x:Name="MouseOver">
<Storyboard>
<DoubleAnimation Duration="0" To=".35" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="fillColor"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimation Duration="0" To=".55" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="contentPresenter"/>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="SelectionStates">
<VisualState x:Name="Unselected"/>
<VisualState x:Name="Selected">
<Storyboard>
<DoubleAnimation Duration="0" To=".75" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="fillColor2"/>
<ColorAnimation Duration="0" To="{StaticResource TransparentDarkDarkColor}" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)" Storyboard.TargetName="fillColor2" d:IsOptimized="True"/>
</Storyboard>
</VisualState>
<VisualState x:Name="SelectedUnfocused"/>
</VisualStateGroup>
<VisualStateGroup x:Name="FocusStates">
<VisualState x:Name="Focused"/>
<VisualState x:Name="Unfocused"/>
</VisualStateGroup>
<VisualStateGroup x:Name="LayoutStates">
<VisualState x:Name="AfterLoaded"/>
<VisualState x:Name="BeforeLoaded"/>
<VisualState x:Name="BeforeUnloaded"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Rectangle x:Name="fillColor" Fill="#FFBADDE9" IsHitTestVisible="False" Opacity="0" RadiusY="1" RadiusX="1"/>
<Rectangle x:Name="fillColor2" Fill="#FFBADDE9" IsHitTestVisible="False" Opacity="0" RadiusY="1" RadiusX="1"/>
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>