databind the Source property of the WebBrowser in WPF

I've amended Todd's excellent answer a little to produce a version that copes with either strings or Uris from the Binding source:

public static class WebBrowserBehaviors
{
    public static readonly DependencyProperty BindableSourceProperty =
        DependencyProperty.RegisterAttached("BindableSource", typeof(object), typeof(WebBrowserBehaviors), new UIPropertyMetadata(null, BindableSourcePropertyChanged));

    public static object GetBindableSource(DependencyObject obj)
    {
        return (string)obj.GetValue(BindableSourceProperty);
    }

    public static void SetBindableSource(DependencyObject obj, object value)
    {
        obj.SetValue(BindableSourceProperty, value);
    }

    public static void BindableSourcePropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
    {
        WebBrowser browser = o as WebBrowser;
        if (browser == null) return;

        Uri uri = null;

        if (e.NewValue is string )
        {
            var uriString = e.NewValue as string;
            uri = string.IsNullOrWhiteSpace(uriString) ? null : new Uri(uriString);
        }
        else if (e.NewValue is Uri)
        {
            uri = e.NewValue as Uri;
        }

        browser.Source = uri;
    }

The problem is that WebBrowser.Source is not a DependencyProperty. One workaround would be to use some AttachedProperty magic to enable this ability.

public static class WebBrowserUtility
{
    public static readonly DependencyProperty BindableSourceProperty =
        DependencyProperty.RegisterAttached("BindableSource", typeof(string), typeof(WebBrowserUtility), new UIPropertyMetadata(null, BindableSourcePropertyChanged));

    public static string GetBindableSource(DependencyObject obj)
    {
        return (string) obj.GetValue(BindableSourceProperty);
    }

    public static void SetBindableSource(DependencyObject obj, string value)
    {
        obj.SetValue(BindableSourceProperty, value);
    }

    public static void BindableSourcePropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
    {
        WebBrowser browser = o as WebBrowser;
        if (browser != null)
        {
            string uri = e.NewValue as string;
            browser.Source = !String.IsNullOrEmpty(uri) ? new Uri(uri) : null;
        }
    }

}

Then in your xaml do:

<WebBrowser ns:WebBrowserUtility.BindableSource="{Binding WebAddress}"/>