Ajax验证在jquery验证引擎中不起作用

我不熟悉jquery验证引擎，并在asp.net mvc应用程序中使用它验证ItemNo。在我看来，我正在使用以下代码：

@Html.TextBoxFor(model => model.ItemNo, new { @class="validate[required,ajax[ajaxCheckItemNo]]" })

我的jquery.validationEngine-en.js中的以下代码

"ajaxCheckItemNo": {
                // remote json service location
                "url": "/DrugManager/IsItemNoAlreadyExists",
                "extraDataDynamic": ['#ItemNo'],
                // error
                "alertText": "* This name is already taken",
                // if you provide an "alertTextOk", it will show as a green prompt when the field validates
                "alertTextOk": "* This name is available",
                // speaks by itself
                "alertTextLoad": "* Validating, please wait"
            }

以及我的控制器中的以下代码

[HttpGet]
    public JsonResult IsItemNoAlreadyExists(string ItemNo, int DrugID = 0, bool IsAddForm = true)
    {
        bool? ReturnValue = null;

        try
        {
            /* returns true/false */
            ReturnValue = ObjDrugManager.IsItemNoAlreadyExists(ItemNo, DrugID, IsAddForm);
        }
        catch (Exception ex)
        {
            /* Catch Exception Here */                
        }

        return Json(new { ReturnValue });

当我运行代码时，服务器代码也会返回值，但在我的视图中，只有加载消息显示如下

        public JsonResult IsItemNoAlreadyExists(string ItemNo, int DrugID = 0, bool IsAddForm = true)
        {
            bool? ReturnValue = null;
     ArrayList validationResult = new ArrayList();
            validationResult.Add("ItemNo");
            try
            {
                /* returns true/false */
                ReturnValue = ObjDrugManager.IsItemNoAlreadyExists(ItemNo, DrugID, IsAddForm);

 if(ReturnValue ==false)
            {
                validationResult.Add(ReturnValue );
                validationResult.Add("Error message.");
            }
            else{
                validationResult.Add(ReturnValue);
                validationResult.Add("success message");
            }       
            }
            catch (Exception ex)
            {
                /* Catch Exception Here */                
            }

            return Json(validationResult, JsonRequestBehavior.AllowGet });
    }

---

我通过在ajax响应中以这种格式返回json解决了这个问题

["field_id",true]