access a ListPicker Control inside a ListBox

In a WP7 app , How to access a ListPicker Control that is in a ListBox itemtemplate. here is my code.

<ListBox ItemsSource="{Binding p_FilterItems}" Margin="0,0,0,8" x:Name="FilterListBox" ScrollViewer.VerticalScrollBarVisibility="Disabled" ScrollViewer.HorizontalScrollBarVisibility="Disabled" BorderThickness="0" >
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal" >
                               开发者_JAVA技巧 <TextBlock Text="{Binding p_Filter}" Foreground="#FFC8AB14" FontSize="24" Height="35" Width="152"  />
                                <toolkit:ListPicker ItemsSource="{Binding filterItems}" Height="43" Name="listPicker1" Width="249" FullModeHeader="{Binding p_Filter}" ItemCountThreshold="1" />
                            </StackPanel>
                        </DataTemplate>
                    </ListBox.ItemTemplate>

                </ListBox>