static void Main(string[] args)

        {

            Stopwatch sw = new Stopwatch();

            sw.Start();

            for (int i = ; i < ; i++);

            sw.Stop();

            Console.WriteLine(sw.Elapsed);//显示程序执行的分钟数，执行的时间如果是分钟以上级别的用这个比较合适

            Console.WriteLine(sw.ElapsedMilliseconds);//显示程序执行的秒数

            Console.ReadKey();

        }

 class Program

    {

        static void Main(string[] args)

        {

            Console.WriteLine("start...");

            TestTime tt = new TestTime();

            Thread.Sleep();

            tt.writeTime("");

            Thread.Sleep();

            tt.writeTime("");

            Thread.Sleep();

            tt.writeTime("");

            Console.WriteLine("end...");

        }

    }

    public class TestTime

    {

        Stopwatch sw;

        string path = @"D:\time.txt";

        //统计次数

        int count = ;

        //上次时间

        long lastTime = ;

        public  TestTime()

        {

            sw = new Stopwatch();

            if (File.Exists(path))

            {

                File.WriteAllText(path, "");

            }

            else

            {

                File.Create(path).Close();

            }

            sw.Start();

        }

        public void writeTime(string str)

        {

            count++;

            File.AppendAllText(path, "第" + count.ToString() + "调用，" + "距离上次时间：" + (sw.ElapsedMilliseconds - lastTime) /  + "秒," + str + "\r\n");

            lastTime = sw.ElapsedMilliseconds;

        }

    }