How to detect when a ScrollViewer finishes scrolling?

Question

BTW I'm using UWP in case it matters. So I am using a ListView and all ListViews have a ScrollViewer attached to them (in default template) by default. The problem is that I cannot find an event (on the ListView itself or on its ScrollViewer) that triggers when the ListView finishes scrolling.

I used the scrollViewer.ChangeView() method to automatically scroll to the beginning of the ListView and it uses an animation to scroll to the top, so I think that has something to do with it because the ViewChanged event fires before the animation completes. If I am correct about that then there would have to be a way to determine if the animation is complete because I need to be alerted when the ListView is completely idle again, which is only when the scroll animation completes. Thanks.

Answer 1

You can wire up the scrollViewer's ViewChanged event, and check the IsIntermediate of the event argument.

private void ScrollViewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
{
    if (e.IsIntermediate)
    {
        System.Diagnostics.Debug.WriteLine("scroll ongoing");
    }
    else
    {
        System.Diagnostics.Debug.WriteLine("scroll finish");
    }
}

This event is fired multiple times. When the scroll finishes, IsIntermediate is false.