/// <summary>
 /// 打上一个标记,combobox、combotree 的值暂存到属性 _value 中,设值操作迟延到事件 onLoadSuccess 里进行。
 /// </summary>
 /// <param name="htmlHelper"></param>
 /// <returns></returns>
 public static ExtendHtmlString MarkDelayedSet(this ExtendHtmlString htmlHelper)
 {
     htmlHelper.Builder.MergeAttribute("delay", "true");
     return(htmlHelper);
 }
 /// <summary>
 /// 添加 css 类名。
 /// </summary>
 /// <param name="htmlHelper"></param>
 /// <param name="className"></param>
 /// <returns></returns>
 public static ExtendHtmlString AddCssClass(this ExtendHtmlString htmlHelper, string className)
 {
     htmlHelper.Builder.AddCssClass(className);
     return(htmlHelper);
 }
 /// <summary>
 /// 打上一个标记,form 的 clear 方法将忽略此域。
 /// </summary>
 /// <param name="htmlHelper"></param>
 /// <returns></returns>
 public static ExtendHtmlString MarkNoClear(this ExtendHtmlString htmlHelper)
 {
     htmlHelper.Builder.MergeAttribute("noclear", "true");
     return(htmlHelper);
 }
 /// <summary>
 /// 添加样式。
 /// </summary>
 /// <param name="htmlHelper"></param>
 /// <param name="style"></param>
 /// <returns></returns>
 public static ExtendHtmlString Style(this ExtendHtmlString htmlHelper, string style)
 {
     htmlHelper.Builder.MergeAttribute("style", style);
     return(htmlHelper);
 }