Xamarin form update listView itemSource

You can set the ItemsSource of the ListView to null, and then set it back again, that does a table reload. http://forums.xamarin.com/discussion/18868/tableview-reloaddata-equivalent-for-listview

Ok here is how I solved the problem, first of all I created a "wrapper" that implement INotifyPropertyChanged for the list that I was taking as ItemSource like this :

public class Wrapper : INotifyPropertyChanged
    {
        List<Filiale> list;
        JsonManager jM = new JsonManager ();//retrieve the list

        public event PropertyChangedEventHandler PropertyChanged;
        public NearMeViewModel ()
        {
            list = (jM.ReadData ()).OrderBy (x => x.distanza).ToList();//initialize the list
        }

        public List<Filiale> List{ //Property that will be used to get and set the item
            get{ return list; }

            set{ 
                list = value;
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, 
                        new PropertyChangedEventArgs("List"));// Throw!!
                }
            }
        }

        public void Reinitialize(){ // mymethod
            List = (jM.ReadData ()).OrderBy (x => x.distanza).ToList();
        }

Then in the NearMe class:

Wrapper nearMeVM = new Wrapper();
public NearMe ()
        {

            Binding myBinding = new Binding("List");
            myBinding.Source = nearMeVM;
            myBinding.Path ="List";
            myBinding.Mode = BindingMode.TwoWay;
            listView.SetBinding (ListView.ItemsSourceProperty, myBinding); 
            listView.ItemTemplate = new DataTemplate(typeof(FilialeCell));
            searchBar = new SearchBar {
                Placeholder="Search"
            };
            searchBar.TextChanged += (sender, e) => {
                TextChanged(searchBar.Text);
            };
            var stack = new StackLayout { Spacing = 0 };
            stack.Children.Add (searchBar);
            stack.Children.Add (listView);
            Content = stack;
        }
public void TextChanged(String text){
            if (!String.IsNullOrEmpty (text)) {
                text = text [0].ToString ().ToUpper () + text.Substring (1);
                var filterSedi = nearMeVM.List.Where (filiale => filiale.nome.Contains (text));
                var newList = filterSedi.ToList ();
                nearMeVM.List = newList.OrderBy (x => x.distanza).ToList ();
            } else {
                nearMeVM.Reinitialize ();
            }