PullToRefreshSamplePage.xaml.cs

PullToRefreshSamplePage.xaml.cs

using System.Collections.ObjectModel;
using System.Linq;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace PullToRefreshSampleApp
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            listView.ItemsSource = new ObservableCollection<int>(Enumerable.Range(1, 10));
        }

        private void scrollViewer_Loaded(object sender, RoutedEventArgs e)
        {
            scrollViewer.ChangeView(null, 60.0, null);
        }

        private void scrollViewer_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            listView.Width = e.NewSize.Width;
            listView.Height = e.NewSize.Height;
            scrollViewer.ChangeView(null, 60.0, null);
        }

        bool _isPullRefresh = false;
        private async void scrollViewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
        {
            var sv = sender as ScrollViewer;

            // text change
            textBlock2.Opacity = sv.VerticalOffset / 100.0;
            if (sv.VerticalOffset == 0.0)
                textBlock1.Opacity = 0.7;
            else
                textBlock1.Opacity = 0.3;

            if (sv.VerticalOffset != 0.0)
                _isPullRefresh = true;

            if (!e.IsIntermediate)
            {
                if (sv.VerticalOffset == 0.0 && _isPullRefresh)
                {
                    // insert code...
                    var source = listView.ItemsSource as ObservableCollection<int>;
                    source.Add(source.Max() + 1);

                    await Task.Delay(300);
                }
                _isPullRefresh = false;
                sv.ChangeView(null, 60.0, null);
            }
        }

    }
}

How would you handle orientation? Right now, if I go from portrait to landscape and back again, the "pull down to refresh"-part is always displayed.