WPF ListBox Scroll to end automatically

Question

In my application, I have a ListBox with items. The application is written in WPF.

How can I scroll automatically to the last added item? I want the

Answer 1

A slightly different approach to those presented so far.

You could use the ScrollViewer ScrollChanged event and watch for the content of the ScrollViewer getting larger.

private void ListBox_OnLoaded(object sender, RoutedEventArgs e)
{
    var listBox = (ListBox) sender;

    var scrollViewer = FindScrollViewer(listBox);

    if (scrollViewer != null)
    {
        scrollViewer.ScrollChanged += (o, args) =>
        {
            if (args.ExtentHeightChange > 0)
                scrollViewer.ScrollToBottom();
        };
    }
}

This avoids some issues with the binding to the ListBox ItemsSource changing.

The ScrollViewer can also be found without making the assumption that the ListBox is using the default control template.

// Search for ScrollViewer, breadth-first
private static ScrollViewer FindScrollViewer(DependencyObject root)
{
    var queue = new Queue(new[] {root});

    do
    {
        var item = queue.Dequeue();

        if (item is ScrollViewer)
            return (ScrollViewer) item;

        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(item); i++)
            queue.Enqueue(VisualTreeHelper.GetChild(item, i));
    } while (queue.Count > 0);

    return null;
}

Then attach this to the ListBox Loaded event:

This could be easily modified to be an attached property, to make it more general purpose.