ItemsControl

How to automatically scroll to the last item

 
<ListBox l:ItemsControlHelper.ScrollToLastItem="true" />
 
 

 
public static class ItemsControlHelper
{
    public static readonly DependencyProperty ScrollToLastItemProperty =
        DependencyProperty.RegisterAttached("ScrollToLastItem",
            typeof(bool), typeof(ItemsControlHelper),
            new FrameworkPropertyMetadata(false, OnScrollToLastItemChanged));
 
    public static void SetScrollToLastItem(UIElement sender, bool value)
    {
        sender.SetValue(ScrollToLastItemProperty, value);
    }
 
    public static bool GetScrollToLastItem(UIElement sender)
    {
        return (bool)sender.GetValue(ScrollToLastItemProperty);
    }
 
    private static void OnScrollToLastItemChanged(DependencyObject sender, 
                            DependencyPropertyChangedEventArgs e)
    {
        var itemsControl = sender as ItemsControl;
 
        if (itemsControl != null)
        {
            itemsControl.ItemContainerGenerator.StatusChanged += 
                     (s,a) => OnItemsChanged(itemsControl,s,a);
        }
    }
 
    static void OnItemsChanged(ItemsControl itemsControl, object sender, EventArgs e)
    {
        var generator = sender as ItemContainerGenerator;
        if( generator.Status == GeneratorStatus.ContainersGenerated )
        {
            if (itemsControl.Items.Count > 0)
            {
                ScrollIntoView(itemsControl, 
                 itemsControl.Items[itemsControl.Items.Count - 1]);
            }
        }
    }
 
    private static void ScrollIntoView(ItemsControl itemsControl, object item)
    {
        if (itemsControl.ItemContainerGenerator.Status == 
            GeneratorStatus.ContainersGenerated)
        {
            OnBringItemIntoView(itemsControl, item);
        }
        else
        {
            Func<object, object> onBringIntoView = 
                    (o) => OnBringItemIntoView(itemsControl, item);
            itemsControl.Dispatcher.BeginInvoke(DispatcherPriority.Loaded, 
                  new DispatcherOperationCallback(onBringIntoView));
        } 
    }
 
    private static object OnBringItemIntoView(ItemsControl itemsControl, object item)
    {
        var element = itemsControl.ItemContainerGenerator.
                 ContainerFromItem(item) as FrameworkElement;
        if (element != null)
        {
            element.BringIntoView();
        }
        return null;
    }
}