/// <summary>
        /// Expands this instance.
        /// </summary>
        public void Expand()
        {
            if (Placeholders != null)
            {
                foreach (var placeHolderName in Placeholders)
                {
                    global::Sitecore.Web.UI.WebControls.Placeholder holder = new global::Sitecore.Web.UI.WebControls.Placeholder();
                    holder.Key = placeHolderName.ToLower();
                    this.Controls.Add(holder);
                }
            }

            this.Controls.Cast <Control>().Where(x => x is global::Sitecore.Layouts.IExpandable)
            .Cast <global::Sitecore.Layouts.IExpandable>().ToList().ForEach(x => x.Expand());
        }
        /// <summary>
        /// Placeholders the specified key.
        /// </summary>
        /// <param name="key">The key.</param>
        /// <returns>IEncodedString.</returns>
        public IEncodedString Placeholder(string key)
        {
            key = key.ToLower();
            var placeHolder = Placeholders.FirstOrDefault(x => x.Key == key);

            if (placeHolder == null)
            {
                placeHolder = new global::Sitecore.Web.UI.WebControls.Placeholder {
                    Key = key
                }
            }
            ;
            ParentControl.Controls.Add(placeHolder);

            var sb = new StringBuilder();

            placeHolder.RenderControl(new HtmlTextWriter(new StringWriter(sb)));
            return(Raw(sb.ToString()));
        }