/// <summary>
        /// The subsequent Bind* operations only apply when the Attribute's property is not null.
        /// </summary>
        /// <param name="propertyName"></param>
        /// <returns></returns>
        public FluentBindingRule <TAttribute> WhenIsNotNull(string propertyName)
        {
            var prop = ResolveProperty(propertyName);

            AppendFilter(FilterNode.NotNull(prop));

            return(this);
        }