由于其他的方法，提交json字符串太大，使用JsonValueProviderFactory一个类继承ValueProviderFactory

重写：
  public override IValueProvider GetValueProvider(ControllerContext controllerContext)
        {
            if (controllerContext == null)
                throw new ArgumentNullException("controllerContext");

            if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
                return null;
            var reader = new StreamReader(controllerContext.HttpContext.Request.InputStream);
            var bodyText = reader.ReadToEnd();

            return string.IsNullOrEmpty(bodyText) ? null : new DictionaryValueProvider<object>(JsonConvert.DeserializeObject<ExpandoObject>(bodyText, new ExpandoObjectConverter()), CultureInfo.CurrentCulture);
        }


  [HttpPost]
        public ActionResult GetPage(PageCondition pageCondition)
        {
            var data = UserService.Instance.GetPage(pageCondition);

            var result = data == null ? null : new EasyPageResult
            {
                total = data.Item1,
                rows = data.Item2
            };

            return GetEasyPageResult(result);
        }

bodyText:{"pageCondition":{"Condition":{"Sorting":[],"Filters":[]},"PageFilter":{"CurrentIndex":1,"PageSize":15}}}
pageCondition 是null，请教各位指点指点