在MVC 3.0 App中如何在asp.net mvc Ajax情况下如何接收和显示JSON错误响应

我正在使用CustomErrorHandler属性处理asp.net mvc应用程序中的错误。代码如下：

 public class CustomHandleErrorAttribute : HandleErrorAttribute    // Error handler 
    {
        public override void OnException(ExceptionContext filterContext)
        {
            if (filterContext.ExceptionHandled || !filterContext.HttpContext.IsCustomErrorEnabled)
            {
                return;
            }
            if (new HttpException(null, filterContext.Exception).GetHttpCode() != 500)
            {
                return;
            }
            if (!ExceptionType.IsInstanceOfType(filterContext.Exception))
            {
                return;
            }

            // if the request is AJAX return JSON else view.
            if (filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")
            {
                filterContext.Result = AjaxError(filterContext.Exception.Message, filterContext);
            }
            else
            {
                filterContext.ExceptionHandled = true;
                var controllerName = (string)filterContext.RouteData.Values["controller"];
                var actionName = (string)filterContext.RouteData.Values["action"];
                var model = new HandleErrorInfo(filterContext.Exception, controllerName, actionName);

                filterContext.Result = new ViewResult
                {
                    ViewName = View,
                    MasterName = Master,
                    ViewData = new ViewDataDictionary<HandleErrorInfo>(model),
                    TempData = filterContext.Controller.TempData
                };
            }

        }
        protected JsonResult AjaxError(string message, ExceptionContext filterContext)
        {
            if (String.IsNullOrEmpty(message))
                message = "Something went wrong while processing your request. Please refresh the page and try again.";
            filterContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            filterContext.HttpContext.Response.TrySkipIisCustomErrors = true;
            return new JsonResult { Data = new { ErrorMessage = message }, ContentEncoding = System.Text.Encoding.UTF8, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
        }
    }
}

它具有捕获正常错误和Ajax错误的功能。

如果出现正常错误，我将建立一个错误模型并显示错误视图

但是，如果发生Ajax错误，我想以JSON形式显示错误消息。

我尝试过类似的事情：

function Failed(data) {  // Onfailed call of MVC Ajax form
        alert("Sorry,An error occured while processing your request");
        alert(data.ErrorMessage);
    }

但是，它说的是data.ErrorMessage的未定义，而不是显示实际的错误消息。

请帮助/建议如何处理。

Updated2： 这是如何解决的：

 function Failed(jqXHR, textStatus, errorThrown) {
        var Error = $.parseJSON(jqXHR.responseText);
        alert("Sorry,An error occured while processing your request");
        alert(Error.ErrorMessage);
    }