async protected override Task <IList <object> > LoadMoreItemsOverrideAsync(System.Threading.CancellationToken c, uint count)
{
++loadIndex;
var pg = await PhotosDataSource.Search(tags[loadIndex], random.Next(5, 15));
return(new List <object> {
pg
});
}
async void Init()
{
progress.Visibility = Visibility.Visible;
var pgs = await PhotosDataSource.LoadPhotos(8);
progress.Visibility = Visibility.Collapsed;
foreach (var pg in pgs)
{
photos.Add(pg);
}
photosSource.Source = photos;
var scrollViewer = gridPhotos.GetFirstDescendantOfType <ScrollViewer>();
scrollViewer.ViewChanging += scrollViewer_ViewChanging;
}
async void scrollViewer_ViewChanging(object sender, ScrollViewerViewChangingEventArgs e)
{
ScrollViewer sv = sender as ScrollViewer;
// if the difference between horizontal offset and scrollable width is less than
// INCREMENTAL_LOAD_OFFSET_TRIGGER pixels load next group
if (((sv.ScrollableWidth - e.FinalView.HorizontalOffset) < INCREMENTAL_LOAD_OFFSET_TRIGGER) &&
(PhotosDataSource.IsBusy == false) &&
(PhotosDataSource.HasMoreItems))
{
progress.Visibility = Visibility.Visible;
var newPhotos = await PhotosDataSource.LoadPhotos(1);
progress.Visibility = Visibility.Collapsed;
foreach (var pg in newPhotos)
{
photos.Add(pg);
}
}
}