更新每个笔划的过滤器

Question

我在MVC中使用C＃5.尝试在每次击键时更新我的​​搜索结果。我写过我认为合乎逻辑的内容。在我的视图中，我写了一些Ajax来与我的帖子控制器进行通信。

    @using (Html.BeginForm("Index", "Directory", FormMethod.Post))
    {
        <p>
            Search Employee: <input type="text" name="userName" onkeyup="filterTerm(this.value);" />


        </p>

    }

<script>
    function filterTerm(value) {
        $.ajax({
            type: "POST",
            url: '@Url.Action("Index","Directory")',
            data: JSON.stringify({ userName: value }),
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (msg) {
                $("#senderContent").html(msg.toString);
            },
            error: function () {
                alert("not connected!");
            }
        });
    }
</script>

这是我的控制者：

        [HttpPost]
        public ActionResult Index(string userName)
        {
        /**********Establish Connection********/
        DirectoryEntry dir = createDirectoryEntry();
        DirectorySearcher search = new DirectorySearcher(dir);

        /****Refer to class constructor****/


        /********Create the List to store results in***************/
        List<ADUser> Users = new List<ADUser>();
        string DisplayName = "", SAMAccountName = "", Mail = "", Description = "", Department = "", TelephoneNumber = "", Fax = "";

        /*******Filter parameters************/
        search.Filter = "(&((&(objectCategory=Person)(objectClass=User)))(anr=" + userName + "* ))";
        SearchResultCollection searchresult = search.FindAll();
        search.PropertiesToLoad.Add("Displayname");
        search.PropertiesToLoad.Add("SAMAccountName");
        search.PropertiesToLoad.Add("Mail");
        search.PropertiesToLoad.Add("Description");
        search.PropertiesToLoad.Add("TelephoneNumber");
        search.PropertiesToLoad.Add("Fax");
        search.PropertiesToLoad.Add("Department");

         /*****************Filtering and populating the List****************/    

        if (searchresult != null)
        {
            foreach (SearchResult iResult in searchresult)
            {
                ADUser userAttributes = new ADUser("", "", "", "", "", "", "");

                foreach (string PropertyName in iResult.Properties.PropertyNames)
                {
                    foreach (Object key in iResult.GetDirectoryEntry().Properties[PropertyName])
                    {
                        try
                        {
                            switch (PropertyName.ToUpper())
                            {
                                case "DISPLAYNAME":
                                    DisplayName = key.ToString();
                                    userAttributes.Name = DisplayName;
                                    break;

                                case "SAMACCOUNTNAME":
                                    SAMAccountName = key.ToString();
                                    userAttributes.DomainUserName = SAMAccountName;
                                    break;

                                case "MAIL":
                                    Mail = key.ToString();
                                    userAttributes.EmailAddress = Mail;
                                    break;

                                case "DESCRIPTION":
                                    Description = key.ToString();
                                    userAttributes.JobDescription = Description;
                                    break;

                                case "TELEPHONENUMBER":
                                    TelephoneNumber = key.ToString();
                                    userAttributes.TelephoneNumber = TelephoneNumber;
                                    break;

                                case "FAX":
                                    Fax = key.ToString();
                                    userAttributes.FaxNumber = Fax;
                                    break;

                                case "DEPARTMENT":
                                    Department = key.ToString();
                                    userAttributes.Department = Department;
                                    break;
                            }
                        }
                        catch { }
                    }
                }

                Users.Add(userAttributes);
            }

            return View(Users);
        }
      return View();
     }

我一直在监视Fiddler中发生的事情并且它没有标记问题，但是ajax错误消息会一直提示。我在传递给ajax之前测试了这个值，它正在正确读取值。只是想知道为什么我被提示这个错误。它是我的Ajax中的东西吗？