Xamarin Forms listview databinding

I am currently following this guide: http://www.morganskinner.com/2015/01/xamarin-forms-contacts-search.html I am willing to make a contacts page in my app, like the one showed in the pictures there, still something is not working out as it should for me: I wrote/copied the XAML: ``` <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <SearchBar x:Name="search" Placeholder="Search"/> <ListView x:Name="ProvaView" Grid.Row="1" ItemsSource="{Binding FilteredContacts}" IsGroupingEnabled="true" GroupDisplayBinding="{Binding Key}" GroupShortNameBinding="{Binding Key}"> <ListView.ItemTemplate> <DataTemplate> <TextCell Text="{Binding Name}" TextColor="Black" Detail="{Binding PhoneNumber}" DetailColor="Gray"> </TextCell> </DataTemplate> </ListView.ItemTemplate> </ListView> </Grid> ``` and now I am trying to "display something", not dinamically loaded (yet), from a list of data. I declared a class like this: ``` public class Contact { public string Name { get; set; } public string PhoneNumber { get; set; } } } ``` and now the code behind the xaml is this: ``` public partial class ContactsPage : MasterDetailPage { public List<Contact> FilteredContacts = new List<Contact> { new Contact { Name = "Guido", PhoneNumber = "3292773477" }, new Contact { Name = "Luca", PhoneNumber = "3472737445" }, new Contact { Name = "Luca", PhoneNumber = "3472737445" } }; public ContactsPage() { InitializeComponent(); ProvaView.ItemsSource = FilteredContacts; } } ``` When I launch the app, all I get anyway is an empty listview, with 3 fields but nothing in it. Where am I doing wrong? Also, straight from the page where I am working off, I can't understand the meaning of these Fields associated to the listview: GroupDisplayBinding="{Binding Key}" GroupShortNameBinding="{Binding Key}" and as much as I could look around on the web, I coudln't find any reference to both of them.