asp.net-mvc-3 - ASP.NET MVC3：如何在自定义 AjaxHelper 中启用不显眼的验证

Question

我有一个自定义 AjaxHelper 呈现启用 ajax 的下拉列表。代码如下。帮助程序运行良好，但是当验证失败时它不会添加 input-validation-error 类，因此它不会以我想要的方式与其他表单元素一起突出显示。在 Html 助手中，我可以合并 HtmlHelper.GetUnobtrusiveValidationAttributes() 给出的属性。但是我如何在 AjaxHelper 中做到这一点？

    public static MvcHtmlString DropDownList(this AjaxHelper ajaxHelper, string name,
        IEnumerable<SelectListItem> list, string optionLabel,
        AjaxOptions ajaxOptions, object htmlAttributes)
    {
        var tag = new TagBuilder("select");
        StringBuilder options = new StringBuilder();
        tag.MergeAttribute("name", name);
        tag.MergeAttribute("id", name);
        TagBuilder option;

        if (optionLabel != null)
        {
            option = new TagBuilder("option");
            option.MergeAttribute("value", string.Empty);
            option.SetInnerText(optionLabel);
            options.Append(option.ToString());
        }

        foreach (SelectListItem item in list)
        {
            option = new TagBuilder("option");
            option.MergeAttribute("value", item.Value);
            if (item.Selected)
            {
                option.MergeAttribute("selected", "selected");
            }
            option.SetInnerText(item.Text);
            options.Append(option.ToString());
        }
        tag.InnerHtml = options.ToString();

        tag.MergeAttributes(HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        tag.MergeAttributes((ajaxOptions ?? new AjaxOptions()).ToUnobtrusiveHtmlAttributes());
        return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
    }