jQuery MVC 科室异步联动

       //科室改变，级联医生 js
        $("#DepartmentId").change(function () {
            if (isNaN($(this).val())) {
                $("#DoctorId option:gt(0)").remove();
            }
            else {
                $.post('/JK/Json/JsonDoctorList/', { departmentId: $(this).val() }, function (data) {
                    if (data.Success) {
                        $("#DoctorId option:gt(0)").remove();
                        $.each(data.Content, function (i, o) {
                            $("<option />").text(o.Name).val(o.Id).appendTo("#DoctorId");
                        });
                    }
                    else {
                        $.alert(data.ErrorMessage);
                    }
                });
            }
        });

///////controller action
public ActionResult JsonDoctorList(int? departmentId )
        {
            JsonData ret = new JsonData();
            JkDoctorRepository rep = new JkDoctorRepository();
            try
            {
                if (departmentId.HasValue)
                {
                    ret.Content = rep.FindByDepartmentId(departmentId.Value);
                }
            }
            catch (Exception ex)
            {
                ret.Success = false;
                ret.ErrorMessage = ex.Message;
            }
            return Json(ret);
        }