/// <summary>
/// Обработать элементы вверху.
/// </summary>
private async void ProcessUp()
{
isUpWorks = true;
ISupportUpDownIncrementalLoading collection = null;
if (ItemsSource != null)
{
collection = ItemsSource as ISupportUpDownIncrementalLoading;
if (collection == null)
{
var source = ItemsSource as CollectionViewSource;
if (source != null)
{
collection = source.Source as ISupportUpDownIncrementalLoading;
}
}
}
else
{
collection = listView.ItemsSource as ISupportUpDownIncrementalLoading;
}
if (collection != null && collection.HasMoreUpItems)
{
var itemToScroll = await collection.LoadUpAsync((uint)NumberItemsToLoad);
if (itemToScroll != null)
{
listView.ScrollIntoView(itemToScroll);
}
if (sv.VerticalOffset == 0)
{
sv.ChangeView(null, 1, null, true);
}
}
isUpWorks = false;
}
/// <summary>
/// Обработать элементы внизу.
/// </summary>
private async void ProcessDown()
{
isDownWorks = true;
ISupportUpDownIncrementalLoading collection = null;
if (ItemsSource != null)
{
collection = ItemsSource as ISupportUpDownIncrementalLoading;
if (collection == null)
{
var source = ItemsSource as CollectionViewSource;
if (source != null)
{
collection = source.Source as ISupportUpDownIncrementalLoading;
}
}
}
else
{
collection = listView.ItemsSource as ISupportUpDownIncrementalLoading;
}
if (collection != null && collection.HasMoreDownItems)
{
var itemToScroll = await collection.LoadDownAsync((uint)NumberItemsToLoad);
if (itemToScroll != null)
{
listView.ScrollIntoView(itemToScroll);
}
}
isDownWorks = false;
}