C#知识点StopWatch计时

            Stopwatch stopwatch = new Stopwatch();
            //第一次计时
            stopwatch.Start();
            Console.WriteLine("Stopwatch is running:{0}",stopwatch.IsRunning);//判断当前Stopwatch的状态
            System.Threading.Thread.Sleep(1000);//耗时操作
            stopwatch.Stop();
            Console.WriteLine("Using Elapsed output runTime:{0}", stopwatch.Elapsed.ToString());//这里使用时间差来输出
            Console.WriteLine("Using ElapsedMilliseconds output runTime:{0}", stopwatch.ElapsedMilliseconds);//这里面使用毫秒来输出
            Console.WriteLine("===================================================");
            //第二次计时
            stopwatch.Start();
            System.Threading.Thread.Sleep(1000);//耗时操作
            stopwatch.Stop();
            Console.WriteLine("The second RunTime:{0}", stopwatch.ElapsedMilliseconds);//这里面使用毫秒来输出
            Console.WriteLine("===================================================");
            //第三次计时（这里使用了Restart）
            stopwatch.Restart();//这里使用Restart来启动计时（会把前面的时间清空）
            System.Threading.Thread.Sleep(1000);//耗时操作
            stopwatch.Stop();
            Console.WriteLine("Using Restart, so runTime:{0}", stopwatch.ElapsedMilliseconds);//这里面使用毫秒来输出
            Console.ReadKey();

            const string path = @"D:\StopwatchDemo.txt";

            using (StreamWriter streamWriter = new StreamWriter(path, true, Encoding.UTF8))
            {
                streamWriter.WriteLine("Start");
                streamWriter.Flush();
                Stopwatch stopwatch = Stopwatch.StartNew();
                System.Threading.Thread.Sleep(1000);//耗时操作
                stopwatch.Stop();
                streamWriter.WriteLine("RunTime:{0}", stopwatch.ElapsedMilliseconds);//以毫秒的形式写进文件
                streamWriter.Flush();
            }