ListBox data virtualization is not taking effect

Question

I had 1000 items from xml and loaded them in a List object. List is databound to ListBox which is horizontally oriented so user can flip through items left to right or right

Answer 1

Here is the XAML that is causing UI Virtualization to finally kick in.

        <ListBox x:Name="horizontalListBox"   Height="Auto" ScrollViewer.HorizontalScrollBarVisibility="Auto" >

                <ListBox.ItemsPanel>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel Orientation="Horizontal">

                        </VirtualizingStackPanel>
                    </ItemsPanelTemplate>
                </ListBox.ItemsPanel>
                <ListBox.ItemTemplate>
                    <DataTemplate>

                            <StackPanel>
                                <TextBlock Width="430" Text="{Binding Word}"  TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" TextAlignment="Center" />

                                <Image Height="290" HorizontalAlignment="Center" Name="image1" Stretch="Fill"  Width="430" Source="{Binding ImageFile}" Margin="10,50,10,0" />
                               </StackPanel>

                    </DataTemplate>
                </ListBox.ItemTemplate>
                <ListBox.Background>
                    <SolidColorBrush />
                </ListBox.Background>
            </ListBox>

Answer 2

at the following article it is explained that wrapping a virtualizing UI control in a ScrollViewer will give it infinite space, effectively disabling UI virtualization

http://blogs.msdn.com/b/mcsuksoldev/archive/2010/04/13/performance-characteristics-of-the-silverlight-datagrid.aspx