c#判断一段代码运行所花费的时间

//定义一个时间对象

            System.Diagnostics.Stopwatch oTime = new System.Diagnostics.Stopwatch();

            oTime.Start(); //记录开始时间

            for (int i = 0; i < 10000; i++) {

                int a = i + 25160;

                int b = a - 1000;

            }

            Thread.Sleep(1500);

                oTime.Stop(); //记录结束时间

                MessageBox.Show(oTime.Elapsed.Seconds+"秒"+oTime.Elapsed.Milliseconds + "毫秒");