Windows Phone 8 Can't Update listbox item in XML file after using hardware back button?

Question

Hi All i have a list box and i am saving list box selected item in XML file thats working fine but the problem is that when i will close my app and reopen and add more value to list box my previous value is removed form the xml file and listbox also how
i can save my current added value and previous value in xml file i am using following code :
and iam 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" Background="Red" 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 back end code is follow:
XmlWriterSettings x_W_Settings = new XmlWriterSettings();
x_W_Settings.Indent = true;
using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
using (IsolatedStorageFileStream stream = ISF.OpenFile(filename, FileMode.Create))
XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
using (XmlWriter xmlWriter = XmlWriter.Create(stream, x_W_Settings))
data.Add(new Prediction() { description = App.professionalId });
list_locationAdd.ItemsSource = data;
serializer.Serialize(xmlWriter, data);
protected override void OnNavigatedTo(NavigationEventArgs e)
try
if (list_locationAdd != null)
using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
using (IsolatedStorageFileStream str = ISF.OpenFile(filename, FileMode.Open))
XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
ObservableCollection<Prediction> data = (ObservableCollection<Prediction>)serializer.Deserialize(str);
if (list_locationAdd != null)
this.list_locationAdd.ItemsSource = data;
list_locationAdd.Visibility = Visibility.Visible;
catch (Exception ex)

Answer 1

Can you provide a working sample?  Upload to Onedrive and share it with us.
Matt Small - Microsoft Escalation Engineer - Forum Moderator
If my reply answers your question, please mark this post as answered.
NOTE: If I ask for code, please provide something that I can drop directly into a project and run (including XAML), or an actual application project. I'm trying to help a lot of people, so I don't have time to figure out weird snippets with undefined
objects and unknown namespaces.