html:   

<div class="add_box add_typename">
            <span class="id_name"><i>*</i>範圍值</span>
            <select id="cmdRangeValue_edit" class="easyui-combotree" name="dept" data-options="required:true,multiple:true,checkbox:true," style="width: 200px;"></select>
        </div>
 

jQuery:       

$.get("/Rights/JobViewRange/GetJobViewRangeByID", { JobViewRangeID: id }, function (data) {
                    $.getJSON("/Rights/JobViewRange/GetRangeValueJson",
                        { RangeType: data.RangeType },
                        function (json) {
                            $("#cmdRangeValue_edit").combotree({
                                data: json,//獲取要顯示的json資料
                                valueField: 'id',
                                textField: 'text',
                            });                        
                            $("#cmdRangeValue_edit").combotree("setValues", data.RangeValue);//注意,是：setValues
                        });      
                });
 

MVC-Controller(注1：一定要先生成combotree的所有節點):

//獲取已選中節點的值(多個值用 , 逗號間隔)
     public ActionResult GetJobViewRangeByID(int JobViewRangeID)
        {
            var jobQuery = new JobViewRangeQuery() { JobViewRangeID = JobViewRangeID };
            var job = JobViewRangeService.GetJobViewRange(jobQuery).FirstOrDefault();
            return Json(job, JsonRequestBehavior.AllowGet);
        }
//生成combotree所有節點的json
     public ActionResult GetRangeValueJson(string RangeType)
        {
            if (string.IsNullOrEmpty(RangeType) || string.IsNullOrWhiteSpace(RangeType)) return Content("");
            string json = JobViewRangeService.GetRangeValueJson(RangeType);
            return Content(json);
        }
 

注2：生成combotree所有節點後，再將值的集合，如：RangeValue= "2,3,4,5,8"; 的字串傳遞給combotree

  $("#cmdRangeValue_edit").combotree("setValues", data.RangeValue);