public static MyDbContext MoveToNext(this WorkFlowBag bag, MyDbContext db, string nextNodeId,
                                             string operatorId, string reason, string endNodeId)
        {
            //创建转移日志
            db.CreateInstanceChangeLog(bag.Instance, "3", operatorId, reason, nextNodeId);
            bag.Move(nextNodeId);
            db.WorkFlowInstance.AddOrUpdate(bag.Instance);
            var isFinish = endNodeId == bag.Instance.CurrentNodeID;

            //如果为结束节点
            if (isFinish)
            {
                //记录实例日志
                db.CreateInstanceHistory(bag.Instance, "2", bag.Instance.Note + "\n" + DateTime.Now + "流程已结束");
                //创建转移日志
                db.CreateInstanceChangeLog(bag.Instance, "2", "system", "[sytem]流程自动结束", null);
                //删除示例
                db.WorkFlowInstance.Remove(db.WorkFlowInstance.Find(bag.Instance.WorkFlowInstanceID));
            }

            return(db);
        }