Design-time-only background color in WPF?

Question

In WPF XAML there is the convenient DesignHeight and DesignWidth, for instance in code as

Answer 1

This is the complete solution for DesignBackground:

public class DesignTimeProperties : DependencyObject
    {
        private static readonly Type OwnerType = typeof(DesignTimeProperties);

        #region DesignBackground (attached property)

        public static Brush GetDesignBackground(DependencyObject obj)
        {
            return (Brush)obj.GetValue(DesignBackgroundProperty);
        }

        public static void SetDesignBackground(DependencyObject obj, Brush value)
        {
            obj.SetValue(DesignBackgroundProperty, value);
        }

        public static readonly DependencyProperty DesignBackgroundProperty =
            DependencyProperty.RegisterAttached(
                "DesignBackground",
                typeof (Brush),
                OwnerType,
                new FrameworkPropertyMetadata(Brushes.Transparent,
                    DesignBackgroundChangedCallback));

        public static void DesignBackgroundChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (IsInDesignMode)
            {
                var control = d as Control;
                var brush = e.NewValue as Brush;
                if (control != null && brush != null)
                {
                    control.Background = brush;
                }
            }
        }

        public static bool IsInDesignMode
        {
            get
            {
                return
                    ((bool)
                        DesignerProperties.IsInDesignModeProperty.GetMetadata(typeof (DependencyObject)).DefaultValue);
            }
        }

        #endregion

    }

Usage: