How do I create an Autoscrolling TextBox

Question

I have a WPF application that contains a multiline TextBox that is being used to display debugging text output.

How can I set the TextBox so that as text is appended to

Answer 1

Similar answer to the other answers, but without the statics events and control dictionary. (IMHO, static events are best avoided if possible).

public class ScrollToEndBehavior
{
    public static readonly DependencyProperty OnTextChangedProperty =
                DependencyProperty.RegisterAttached(
                "OnTextChanged",
                typeof(bool),
                typeof(ScrollToEndBehavior),
                new UIPropertyMetadata(false, OnTextChanged)
                );

    public static bool GetOnTextChanged(DependencyObject dependencyObject)
    {
        return (bool)dependencyObject.GetValue(OnTextChangedProperty);
    }

    public static void SetOnTextChanged(DependencyObject dependencyObject, bool value)
    {
        dependencyObject.SetValue(OnTextChangedProperty, value);
    }

    private static void OnTextChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        var textBox = dependencyObject as TextBox;
        var newValue = (bool)e.NewValue;

        if (textBox == null || (bool)e.OldValue == newValue)
        {
            return;
        }

        TextChangedEventHandler handler = (object sender, TextChangedEventArgs args) =>
            ((TextBox)sender).ScrollToEnd();

        if (newValue)
        {
            textBox.TextChanged += handler;
        }
        else
        {
            textBox.TextChanged -= handler;
        }
    }
}

This is just an alternative to the other posted solutions, which were among the best I found after looking for awhile (i.e. concise & mvvm).