一个线程知识点, 一个MongoDB的知识点

 //WINForm窗体中切换前后台线程执行任务:
         protected void RunOnUI(Action action)
         {
             Invoke(action);
         }

         protected void RunOnBg(Action action)
         {
             Task.Factory.StartNew(action);
         }

             //MongoDB创建索引
             if (idx.Count == )
             {
                 tbPoints.Indexes.CreateOne(Builders<GpsPoint>.IndexKeys.Descending(it => it.Sn));
                 tms = Convert.ToInt32((DateTime.Now - dtStart).TotalSeconds);
                 LogHelper.Show($"压缩轨迹 ~~ 创建索引 用时 {tms} 秒");
             }