MVC5中后台提供Json，前台处理Json，绑定给Dropdownlist的例子

<div class="row">
            <div class="col-md-1">国家</div>
            <div class="col-md-11">
                @Html.DropDownListFor(model => model.Director.HometownID, MvcEntitiyFrameWork.ViewModels.HometownViewModel.GetHometownSelectList(), htmlAttributes: new { @class = "form-control", @style = "width:120px;" })
                
            </div>
        </div>

        <div class="row" style="margin-bottom:2px">
            <div class="col-md-1">导演</div>
            <div class="col-md-11">
                @Html.DropDownListFor(model => model.DirectorID, MvcEntitiyFrameWork.ViewModels.DirectorViewModel.GetDirectorSelectList(Model.Director.HometownID.ToString()), htmlAttributes: new { @class = "form-control", @style = "width:120px;" })
                @Html.ValidationMessageFor(model => model.DirectorID, "", new { @class = "text-danger" })
            </div>
        </div>

<script type="text/javascript">
    $("#Director_HometownID").change(    
            function ()
            {
                GetDirector($(this).val());
            }
        );
    function GetDirector(message) {
        var option = {
            url: ‘/Movies/GetDirectorList‘,
            type: ‘get‘,
            chche: false,
            dataType: ‘json‘,
            data: { _htid: message }, //发送服务器数据
            success: function (data) {  //成功事件
                $("#DirectorID").empty();
                
                $.each(data, function (i, item) {
                    $("<option></option>").val(data[i].Value).text(data[i].Text).appendTo($("#DirectorID"));
                    
                });
            },
            error: function (XMLHttpRequest, textStatus, errorThrown) { //发送失败事件
                alert(textStatus );
            }
        };
        //进行异步传输
        $.ajax(option);
    }

   
</script>  

 public ActionResult GetDirectorList(string _htid)
        {
            try
            {
                //方法一 Ok
                //var selectList = db.Directors.Where(a => a.HometownID.ToString() == _htid).Select(a => new SelectListItem
                //{

                //    Text = a.DirectorName,

                //    Value = a.DirectorID.ToString()

                //});

                //return Json(selectList, JsonRequestBehavior.AllowGet);
                //方法二 也Ok
                List<Director> list = db.Database.SqlQuery<Director>("select DirectorID,DirectorName,HometownID from Directors where HometownID=‘" + _htid + "‘").ToList();

                SelectList pList = new SelectList(list, "DirectorID", "DirectorName");

                return Json(pList, JsonRequestBehavior.AllowGet);
            }
            catch (Exception ex)
            {
                return null;
            }

        }