jQuery Validate表单验证帐号是否存在

//验证表单
function validform() {
    return $("#form").validate({
        rules: {
            LoginName: {
                required: true,
                remote: {
                   url: "/AppWorker/LoginNameIsExist",     //后台处理程序
                   type: "post",               //数据发送方式
                   dataType: "json",           //接受数据格式    (一定是json 数据)
                   data: {                     //要传递的数据
                         name: function () {
                            return $("#Name").val();
                         }
                    },
                    dataType: "html",
                    dataFilter: function (data, type) {
                        if (data != "True")
                            return true;
                       else
                            return false;
                   }
               }

            },

        },
        messages: {
            LoginName: {
                required: "必须填写登录帐号",
                remote: "帐号已经存在"
            }
          
        }
    });
}

       /// <summary>
        /// 验证登录帐号是否被占用
        /// </summary>
        /// <returns></returns>
        [LoginActionFilter]
        public bool LoginNameIsExist()
        {
            string name = Request["name"].ToString();
            var obj = studentBLL.GetAll().FirstOrDefault(p => p.LoginName == name);
            return obj != null;//无结果返回false，有结果返回true
        }

   public List<Student> GetAll()
        {
            var mql = StudentSet.SelectAll().Where(StudentSet.isLock.NotEqual(1));
            List<Student> list = studentDAL.GetEntities(mql);
            return list;
            //throw new NotImplementedException();
        }