问xamarin表单:滑动以删除

EN

public partial class MyPage
{
    List<Note> notes;
    string NotesFile {
        get {
            var documents = Environment.GetFolderPath (Environment.SpecialFolder.Personal);
            return System.IO.Path.Combine (documents, "notes.json");
        }
    }
    public MyPage()
    {
        BuildContent();
        LoadNotes ();
        ReloadListContents ();

        AddNoteButton.Clicked += (sender, args) => {
            var note = new Note("typ...");
            notes.Add(note);
            EditNote(note);
        };

        NoteListView.ItemTapped += (sender, row) =>
        {
            NoteListView.SelectedItem = null;
            Note note = (Note)row.Item;
            EditNote(note);
        };

        buttonDelete.Clicked += (sender, args) =>{
            notes.RemoveAt(0);
            DisplayAlert("Delete", "Row deleted", "OK");
        };
    }

{
    public ListView NoteListView = new ListView ();
    public Button AddNoteButton;
    public Button buttonDelete;
    private void BuildContent() 
    {
        AddNoteButton = new Button
        {
            Text = "Add New Note",
            TextColor = Color.White,
            HorizontalOptions = LayoutOptions.Center,
            VerticalOptions = LayoutOptions.Center
        };
        buttonDelete = new Button
        {
            Text = "Delete Note ",
            TextColor = Color.White,
            HorizontalOptions = LayoutOptions.Center,
            VerticalOptions = LayoutOptions.Center
        };

        Content = new StackLayout
        {
            BackgroundColor = Color.Black,
            Children = {
                new Label {
                    Text = "Note Taker",
                    TextColor = Color.White
                },
                NoteListView,
                AddNoteButton,
                buttonDelete
            }
        };
    }