How to Save Listbox item in Windows Phone 8

Question

I have a two listbox one listbox i am showing data from my JSON we servive and another listbox i am showing selected item from frist listbox it is working fine but the problem is that when i come back from my application and reopen app i want to show second list box with selected item i am using following code:

     <Grid x:Name="ContentPanel" Grid.Row="2" Margin="15,10,15,0">
                <ListBox Name="list_location" Tap="list_location_Tap" Foreground="Black">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <TextBlock x:Name="item_name" Text="{Binding description, Mode=OneWay}" Padding="5,15,5,15" TextWrapping="Wrap" FontSize="{StaticResource PhoneFontSizeLarge}"/>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                   
                </ListBox>

                <ListBox Name="list_locationAdd"  Foreground="Black" Visibility="Collapsed">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <TextBlock x:Name="item_name" Text="{Binding description, Mode=OneWay}" Padding="5,15,5,15" TextWrapping="Wrap" FontSize="{StaticResource PhoneFontSizeLarge}"/>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>

            </Grid>
and my .cs code is as follow:
list_locationAdd.Visibility = Visibility.Visible;
                list_location.Visibility = Visibility.Collapsed;


                if (!list_locationAdd.Items.Contains(list_location.SelectedItem))
                {
                    list_locationAdd.Items.Add(list_location.SelectedItem);

                }

thanks: