ItemsControl

How to automatically scroll to the last item (마지막 항목으로 자동 스크롤하는 방법)

<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, object item)
  {
    var element = itemsControl.ItemContainerGenerator.ContainerFromItem(item) as FrameworkElement;
    if(element != null)
    {
      element.BringIntoView();
    }

    return null;
  }
}