将数据从控制器传递给js，反之亦然

Question

这是我的控制器类：

public class TestController : Controller
    {
        log4net.ILog _logger = log4net.LogManager.GetLogger(typeof(HomeController));
        //
        // GET: /Test/

        public ActionResult Index()
        {
            List<SelectListItem> testlist = new List<SelectListItem>();
            SelectListItem s = new SelectListItem();
            s.Value = "--Select One--";
            s.Text = "--Select One--";
            testlist.Add(s);
            ViewBag.Items = testlist;

            return View();
        }

        public ActionResult PassToView()
        {
            List<SelectListItem> testlist = new List<SelectListItem>();
            SelectListItem s = new SelectListItem();
            s.Text = "data1";
            s.Value = "data1";
            testlist.Add(s);

            s = new SelectListItem();
            s.Text = "data2";
            s.Value = "data2";
            testlist.Add(s);

            s = new SelectListItem();
            s.Text = "data3";
            s.Value = "data3";
            testlist.Add(s);

            s = new SelectListItem();
            s.Text = "data4";
            s.Value = "data4";
            testlist.Add(s);

            s = new SelectListItem();
            s.Text = "data5";
            s.Value = "data5";
            testlist.Add(s);

            return Json(testlist, JsonRequestBehavior.AllowGet);
        }

        public ActionResult PassToController(string SelectedValue)
        {
            _logger.Info("Selected value is :" + SelectedValue);
            return View();
        }

    }

这是我的观点：

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>

@Html.DropDownList("ddlItems", (IEnumerable<SelectListItem>)ViewBag.Items, new { @id = "ddlItems", @class = "dropdownlist", onchange = "ddlItemChange();" }) 
<script  type="text/javascript">
    $(document).ready(function () {
        $.getJSON("/Test/PassToView", function (data) {
            var selectList = $("#ddlItems");
            selectList.empty();
            $.each(data, function (index, optionData) {
                var option = $('<option>').text(optionData.Text).val(optionData.Value);
                selectList.append(option);
            });
            selectList.trigger("chosen:updated");
        });
    });

    function ddlItemChange() {
        var selectedvalue = $("select[name='ddlItems']").val();
        $.post("/Test/PassToController", { SelectedValue: selectedvalue });
        return false;
    }

</script>

下拉列表未填写。请参阅附图。

你可以告诉我我做错了吗？ 谢谢你的时间。