Determining Design Mode from Attached Properties

gistfile1.cs

private bool IsDesignMode {
    get {
        DependencyProperty isDesignModeProperty = (DependencyProperty)AppDomain.CurrentDomain.GetData(“IsDesignModeProperty”);
        return isDesignModeProperty == null ? false : true.Equals(isDesignModeProperty.GetValue(this));
    }
}