@section Scripts {
  @Scripts.Render("~/bundles/jqueryval")
}

namespace System.Web.Mvc.Html
{
    /// <summary>
    /// MVC中對HtmlHelper擴展方法
    /// </summary>
    public static class MvcHtmlExtensions
    {
        /// <summary>
        /// 從ModelState中返回指定鍵(jian)對(dui)應的(de)驗證的(de)錯誤消息(xi)
        /// </summary>
        /// <typeparam name="TModel"></typeparam>
        /// <typeparam name="TProperty"></typeparam>
        /// <param name="htmlHelper"></param>
        /// <param name="expression"></param>
        /// <returns></returns>
        public static MvcHtmlString ValidationMessageTextFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression)
        {

            var fieldName = ExpressionHelper.GetExpressionText(expression);

            var modelState = htmlHelper.ViewData.ModelState;
            if (!modelState.Keys.Contains(fieldName))
                return null;
            if (modelState[fieldName].Errors.Count == 0)
                return null;
            IList<string> errList = new List<string>();
            modelState[fieldName].Errors.ToList().ForEach(i =>
            {
                errList.Add(i.ErrorMessage);
            });
            return MvcHtmlString.Create(string.Join(",", errList));

        }
    }
}