/// <summary>
        /// 添加一个导航。
        /// </summary>
        /// <param name="caption">标题。</param>
        /// <param name="position">导航位置。</param>
        /// <param name="itemBuilder">导航项建造者。</param>
        /// <param name="classes">样式名称。</param>
        /// <returns>导航建造者。</returns>
        public NavigationBuilder Add(LocalizedString caption, string position, Action <NavigationItemBuilder> itemBuilder, IEnumerable <string> classes = null)
        {
            var childBuilder = new NavigationItemBuilder();

            childBuilder.Caption(caption);
            childBuilder.Position(position);
            itemBuilder(childBuilder);
            Contained.AddRange(childBuilder.Build());

            if (classes == null)
            {
                return(this);
            }
            foreach (var className in classes)
            {
                childBuilder.AddClass(className);
            }

            return(this);
        }
        /// <summary>
        /// 添加一个导航。
        /// </summary>
        /// <param name="caption">标题。</param>
        /// <param name="position">导航位置。</param>
        /// <param name="itemBuilder">导航项建造者。</param>
        /// <param name="classes">样式名称。</param>
        /// <returns>导航建造者。</returns>
        public NavigationBuilder Add(LocalizedString caption, string position, Action<NavigationItemBuilder> itemBuilder, IEnumerable<string> classes = null)
        {
            var childBuilder = new NavigationItemBuilder();

            childBuilder.Caption(caption);
            childBuilder.Position(position);
            itemBuilder(childBuilder);
            Contained.AddRange(childBuilder.Build());

            if (classes == null)
                return this;
            foreach (var className in classes)
                childBuilder.AddClass(className);

            return this;
        }