Me gustaría crear un borde alrededor del elemento seleccionado actualmente dentro de unLongListSelector, pero estoy teniendo problemas para conseguir la implementación adecuada. A partir de referenciashttp://code.msdn.microsoft.com/wpapps/Highlight-a-selected-item-30ced444 He intentado seguir el código de ejemplo creando un personalizadoStyle para administrar el cambio de elemento seleccionado, aunque estoy tratando de colocar un borde alrededor de una imagen en lugar de un cuadro de texto. Además, tengo una costumbreItemTemplate como miDataTemplate para miLongListSelector que gestiona el tamaño de mis imágenes encuadernadas y controla un requeridoContextMenu para cada articulo

Por alguna razón, tengo problemas para adaptar la muestra para colocar un borde alrededor de un elemento seleccionado, pero lo que tengo hasta ahora es el siguiente

MainPage.xaml

<phone:PhoneApplicationPage.Resources>

    <DataTemplate x:Key="ItemTemplate">
        <!--<Border x:Name="brd" CornerRadius="10" BorderBrush="{StaticResource PhoneAccentBrush}" Width="Auto" BorderThickness="3">-->
        <Border x:Name="brd" CornerRadius="10" Width="Auto" BorderThickness="3">
            <Viewbox Width="108" Height="108">
                <Image x:Name="recentImage" Source="{Binding Source}" Margin="6,6" Width="108"/>
            </Viewbox>
            <toolkit:ContextMenuService.ContextMenu>
                <toolkit:ContextMenu x:Name="imgListContextMenu" Background="{StaticResource PhoneChromeBrush}">
                    <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="edit" Click="editContextMenuItem_Click"/>
                    <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="favorite" Click="favoriteContextMenuItem_Click"/>
                    <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="delete" Click="deleteContextMenuItem_Click"/>
                </toolkit:ContextMenu>
            </toolkit:ContextMenuService.ContextMenu>
        </Border>
    </DataTemplate>

</phone:PhoneApplicationPage.Resources>

...

<phone:LongListSelector x:Name="Recent" Margin="0" 
                                    Style="{StaticResource MyLongListSelectorStyle}"
                                    SelectionChanged="recent_SelectionChanged" 
                                    toolkit:TiltEffect.IsTiltEnabled="True"
                                    LayoutMode="Grid" GridCellSize="108,108"
                                    ItemTemplate="{StaticResource ItemTemplate}"
                                    />

App.xaml

<Style x:Key="MyLongListSelectorStyle" TargetType="phone:LongListSelector" >
        <!--<Setter Property="LayoutMode" Value="List"/>-->
        <Setter Property="LayoutMode" Value="Grid"/>
        <!--<Setter Property="FontFamily" Value="Times New Roman"/>-->
        <Setter Property="ItemTemplate">
            <Setter.Value>
                <DataTemplate>
                    <UserControl>
                        <Border x:Name="MyBorder" Background="Transparent">
                            <VisualStateManager.VisualStateGroups  >
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal" />
                                    <VisualState x:Name="Selected">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background)" Storyboard.TargetName="MyBorder">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneAccentBrush}"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <!--<StackPanel>
                                <TextBlock x:Name="textBlock" Text="{Binding}" TextWrapping="Wrap" Style="{StaticResource PhoneTextSubtleStyle}"/>
                            </StackPanel>-->
                        </Border>
                    </UserControl>
                </DataTemplate>
            </Setter.Value>
        </Setter>
    </Style>

MainPage.xaml.cs

private void recent_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var s = sender as LongListSelector;
        var item = (sender as LongListSelector).SelectedItem;
        if (item == null)
            return;

        // Get item of LongListSelector.
        List<UserControl> listItems = new List<UserControl>();
        GetItemsRecursive<UserControl>(Recent, ref listItems);

        // Selected.
        if (e.AddedItems.Count > 0 && e.AddedItems[0] != null)
        {
            foreach (UserControl userControl in listItems)
            {
                if (e.AddedItems[0].Equals(userControl.DataContext))
                {
                    VisualStateManager.GoToState(userControl, "Selected", true);
                }
            }
        }
        // Unselected.
        if (e.RemovedItems.Count > 0 && e.RemovedItems[0] != null)
        {
            foreach (UserControl userControl in listItems)
            {
                if (e.RemovedItems[0].Equals(userControl.DataContext))
                {
                    VisualStateManager.GoToState(userControl, "Normal", true);
                }
            }
        }
    }

public static void GetItemsRecursive<T>(DependencyObject parents, ref List<T> objectList) where T : DependencyObject
    {
        var childrenCount = VisualTreeHelper.GetChildrenCount(parents);

        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parents, i);

            if (child is T)
            {
                objectList.Add(child as T);
            }

            GetItemsRecursive<T>(child, ref objectList);
        }

        return;
    }

Estoy atascado en qué hacer desde aquí, ¿alguna idea?

EDIT ** modificó ligeramente la implementación pero aún no funciona.

MainPage.xaml

<phone:PhoneApplicationPage.Resources>

    <Style x:Key="MyLongListSelectorStyle" TargetType="phone:LongListSelector" >
        <!--<Setter Property="LayoutMode" Value="List"/>-->
        <Setter Property="LayoutMode" Value="Grid"/>
        <!--<Setter Property="FontFamily" Value="Times New Roman"/>-->
        <Setter Property="ItemTemplate">
            <Setter.Value>
                <DataTemplate>
                    <UserControl>
                        <!--<Border x:Name="MyBorder" Background="Transparent">-->
                        <Border x:Name="MyBorder" Background="Transparent">
                            <VisualStateManager.VisualStateGroups  >
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal" />
                                    <VisualState x:Name="Selected">
                                        <Storyboard>
                                            <!--<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background)" Storyboard.TargetName="MyBorder">-->
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderThickness" Storyboard.TargetName="brd">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneAccentBrush}"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Border x:Name="brd" CornerRadius="10" Width="Auto" BorderThickness="3">
                                <!--<Border x:Name="brd" CornerRadius="10" Width="Auto" BorderThickness="3">-->
                                <Viewbox Width="108" Height="108">
                                    <Image x:Name="recentImage" Source="{Binding Source}" Margin="6,6" Width="108"/>
                                </Viewbox>
                                <toolkit:ContextMenuService.ContextMenu>
                                    <toolkit:ContextMenu x:Name="imgListContextMenu" Background="{StaticResource PhoneChromeBrush}">
                                        <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="edit" Click="editContextMenuItem_Click"/>
                                        <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="favorite" Click="favoriteContextMenuItem_Click"/>
                                        <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="delete" Click="deleteContextMenuItem_Click"/>
                                    </toolkit:ContextMenu>
                                </toolkit:ContextMenuService.ContextMenu>
                            </Border>
                            <!--<StackPanel>
                                <TextBlock x:Name="textBlock" Text="{Binding}" TextWrapping="Wrap" Style="{StaticResource PhoneTextSubtleStyle}"/>
                            </StackPanel>-->
                        </Border>
                    </UserControl>
                </DataTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</phone:PhoneApplicationPage.Resources>

...

<phone:LongListSelector x:Name="Recent" Margin="0" 
                                    Style="{StaticResource MyLongListSelectorStyle}"
                                    SelectionChanged="recent_SelectionChanged" 
                                    toolkit:TiltEffect.IsTiltEnabled="True"
                                    LayoutMode="Grid" GridCellSize="108,108"

                                    />

MainPage.xaml.cs

//remains the same