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

The most easiest way to achieve autoscrolling is to hook on the CollectionChanged event. Just add that functionality to a custom class which derives from ListBox control:

using System.Collections.Specialized;
using System.Windows.Controls;
using System.Windows.Media;

namespace YourProgram.CustomControls
{
  public class AutoScrollListBox : ListBox
  {
      public AutoScrollListBox()
      {
          if (Items != null)
          {
              // Hook to the CollectionChanged event of your ObservableCollection
              ((INotifyCollectionChanged)Items).CollectionChanged += CollectionChange;
          }
      }

      // Is called whenever the item collection changes
      private void CollectionChange(object sender, NotifyCollectionChangedEventArgs e)
      {
          if (Items.Count > 0)
          {
              // Get the ScrollViewer object from the ListBox control
              Border border = (Border)VisualTreeHelper.GetChild(this, 0);
              ScrollViewer SV = (ScrollViewer)VisualTreeHelper.GetChild(border, 0);

              // Scroll to bottom
              SV.ScrollToBottom();
          }
      }
  }
}

Add the namespace of the custom control to your WPF window and use the custom ListBox control:

<Window x:Class="MainWindow"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local="clr-namespace:YourProgram"
         xmlns:cc="clr-namespace:YourProgram.CustomControls"
         mc:Ignorable="d" 
         d:DesignHeight="450" d:DesignWidth="800">

    <cc:AutoScrollListBox ItemsSource="{Binding YourObservableCollection}"/>

</Window>

Answer 2

The best solution is to use the ItemCollection object inside the ListBox control this collection was specially designed to content viewers. It has a predefined method to select the last item and keep a cursor position reference....

myListBox.Items.MoveCurrentToLast();
myListBox.ScrollIntoView(myListBox.Items.CurrentItem);

Answer 3

Keep in mind that listBox.ScrollIntoView(listBox.Items[listBox.Items.Count - 1]); works only if you have no duplicate items. If you have items with the same contents it scrolls down to the first find.

Here is the solution I found:

ListBoxAutomationPeer svAutomation = (ListBoxAutomationPeer)ScrollViewerAutomationPeer.CreatePeerForElement(myListBox);

IScrollProvider scrollInterface = (IScrollProvider)svAutomation.GetPattern(PatternInterface.Scroll);
System.Windows.Automation.ScrollAmount scrollVertical = System.Windows.Automation.ScrollAmount.LargeIncrement;
System.Windows.Automation.ScrollAmount scrollHorizontal = System.Windows.Automation.ScrollAmount.NoAmount;
//If the vertical scroller is not available, the operation cannot be performed, which will raise an exception. 
if ( scrollInterface.VerticallyScrollable )
    scrollInterface.Scroll(scrollHorizontal, scrollVertical);