Bootstrap validation errors

Helper

        public static MvcHtmlString BootStrapValidationSummary(this HtmlHelper helper)
        {
            if (helper.ViewData.ModelState.Keys.Any(k => helper.ViewData.ModelState[k].Errors.Any()))
            {
                return MvcHtmlString.Create("<div class='alert alert-danger'>" 
                                                + "<button class='close' data-dismiss='alert' aria-hidden='true'>&times;</button>" 
                                                + helper.ValidationSummary(false, "Please check the following:")
                                                + "</div>");
            }
            return null;
        }