How to bind details list to master list

Question

Hello,
I have json file with a lot objects in it. Depending on user selection object are sometimes different. For example, if user selects option #1 there are 4 objects in json string. If user selects option #2 there are 7 objects in json string. I need to update
my UI to show selected objects. Problem is that I'm using Listbox to show items. I need Listpicker inside that listbox. Listpicker #1 should be for option #1, listpicker #2 for option #2 and so on. My question is how can I bind ItemSource to listboxes as they
are already inside ListBox so I can't access them with code?
Greetings.

Answer 1

There's no need to access listpicker which is inside listbox, rather simply data-bind the listpickers with json data parsed.
e.g: 
public class OptionsClass1
public string OptionsMainValue1 { get; set; }
public List<string> optionSubValue1 { get; set; }
Similarly create classes for other listpickers & databind these properties to the listpicker , therefor inside xaml, for ListPicker 1, the binding properties would be 'OptionsMainValue1' & optionSubValue1 , similarly for ListPicker 2, it would be
'OptionsMainValue2' & 'optionsSubValue2' and so on..
http://developer.nokia.com/community/wiki/Using_Crypto%2B%2B_library_with_Windows_Phone_8
Thank you for your reply. I tried that and I end up with null exception. Here is my code:
public class Option1
public string MainOption1{ get; set; }
public List<string> SubOption1{ get; set; }
and function:
ObservableCollection<Option1> list = new ObservableCollection<Option1>();
private void Step2()
var responseString = response.Content.ToString();
JObject o = JObject.Parse(responseString);
for (int num= 0; num< o["jsonObject"].Count(); num++)
Option1 option1 = new Option1();
option1.MainOption1 = "Some json string";
option1.SubOption1.Add(option1.MainOption1);
Listbox.ItemSource = list;
My XAML:
<ListBox x:Name="listbox" Margin="0,85,0,45" Background="#FFC9C9C9">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<toolkit:ListPicker ItemsSource="{Binding SubOption1}">
<toolkit:ListPicker.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding MainOption1}"/>
</DataTemplate>
</toolkit:ListPicker.ItemTemplate>
</toolkit:ListPicker>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>