Passing data from Page2 to Page1

Question

Hi, in my Windows Phone 8.1 RT project, I have a list of countries in Page2 (in a ListView) and a textblock in Page1. I would like to have the item selection form the list in Page2 to transferred to the textblock in Page1. 

 

  

This is what I've done in the ItemClick event of the ListView. Here's the snippet for that:

 

private void ListofallCountries_ItemClick(object sender, ItemClickEventArgs e)

{

   var item_selection_list = ListofallCountries.SelectedItem.ToString();

   Frame.Navigate(typeof(page2_country_list_plus_phone_number_extractor), item_selection_list);

}

How do I get to have item_selection_list (that I suppose has the selected item in the string format) display in the textblock in Page1?