/// <summary>
        /// 栏目下拉列表
        /// </summary>
        /// <param name="htmlHelper">被扩展的htmlHelper实例</param>
        /// <param name="expression">选择实体中栏目属性的lamda表达式</param>
        /// <param name="contentTypeKey">数据模型Id</param>
        /// <param name="exceptFolderId">需要去掉的ID</param>
        /// <param name="folderLevel">栏目层级(默认取站点配置)</param>
        public static MvcHtmlString FolderDropDownListFor <TModel>(this HtmlHelper <TModel> htmlHelper, Expression <Func <TModel, int> > expression, string contentTypeKey = null, int exceptFolderId = 0, bool?onlyModerated = null, int?folderLevel = null)
        {
            string getChildFoldersUrl = SiteUrls.Instance().GetChildContentFolders(contentTypeKey, exceptFolderId, onlyModerated);
            FolderServiceHelper folderServiceHelper = new FolderServiceHelper(contentTypeKey, exceptFolderId, onlyModerated);

            if (folderLevel == null)
            {
                folderLevel = 4;
            }
            return(htmlHelper.LinkageDropDownListFor <TModel, int>(expression, 0, folderLevel.Value, folderServiceHelper.GetRootFolderDictionary(), folderServiceHelper.GetParentId, folderServiceHelper.GetChildrenDictionary, getChildFoldersUrl));
        }
        /// <summary>
        /// 栏目下拉列表
        /// </summary>
        /// <param name="htmlHelper">被扩展的htmlHelper实例</param>
        /// <param name="name">控件name属性</param>
        /// <param name="value">选中的栏目Id</param>
        /// <param name="contentTypeKey">数据模型Id</param>
        /// <param name="exceptFolderId">需要去掉的ID</param>
        /// <param name="folderLevel">栏目层级(默认取站点配置)</param>
        public static MvcHtmlString FolderDropDownList(this HtmlHelper htmlHelper, string name, int value, string contentTypeKey = null, int exceptFolderId = 0, bool?onlyModerated = null, int?folderLevel = null, string optionLabel = "请选择")
        {
            string getChildFoldersUrl = SiteUrls.Instance().GetChildContentFolders(contentTypeKey, exceptFolderId, onlyModerated);

            FolderServiceHelper folderServiceHelper = new FolderServiceHelper(contentTypeKey, exceptFolderId, onlyModerated);

            if (folderLevel == null)
            {
                folderLevel = 4;
            }
            return(htmlHelper.LinkageDropDownList <int>(name, value, 0, folderLevel.Value, folderServiceHelper.GetRootFolderDictionary(), folderServiceHelper.GetParentId, folderServiceHelper.GetChildrenDictionary, getChildFoldersUrl, optionLabel));
        }