将所选值传递给jQuery的select2 ajax调用

Question

我试图将额外参数（所选值）传递给multiple select2内的ajax调用：

 $("#ddlMultiCourse").select2({
    placeholder: "Search for Course",
    minimumInputLength: 1,
    allowClear: true,
    ajax: { // instead of writing the function to execute the request we use Select2's convenient helper
        url: url,//GetCourseList
        type: "POST",
        dataType: 'json',
        delay: 250,
        data: function (params) {
            return {
                term: params.term, // search term
                value: $("#ddlMultiCourse").val()//extra parameter
            };
        },
        processResults: function (data, params) {              

            return {
                results: data

            };
        }

    }
});

我实际上想要将另一个参数传递给ajax调用...以前选择的值..

 public JsonResult GetCourseList(string term, string[] value)
    {
        try
        {

            var _courseList = _db.MultiCourses
                            .Where(x => x.CourseCode.StartsWith(term))
                            .Select(x => new 
                            {
                                id=x.Id,
                                text=x.CourseCode
                            }).ToList();


            return Json(_courseList, JsonRequestBehavior.AllowGet);

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

现在我的价值为null。