C# 程序时间

1.DateTime
           DateTime now = System.DateTime.Now;
           now.ToString();                                                       //显示: 2006/08/30 17:31:02
           now.ToString("yyyy-mm-dd hh:MM:ss");                //显示: 2006-08-30 05:39:11
           now.ToString("yyyy-mm-dd HH:mm:ss");                //显示: 2006-08-30 17:40:50
          System.DateTime.MaxValue.ToString();                   //显示: 9999/12/31 23:59:59
          System.DateTime.MinValue.ToString();                   //显示: 0001/01/01 0:00:00
         now.ToLongDateString();                                         //显示: 2006年8月30日
         now.ToLongTimeString();                                         //显示: 17:34:23
         now.ToShortTimeString();                                         //显示: 17:34
         now.ToString() + " " + now.Millisecond.ToString();   //显示: 2006/08/30 17:35:19 484

2.程序运行时间:(单位 :  毫秒)
        System.Diagnostics ;  //名称空间
             int x = 0;
             int nu = 0;       
            Stopwatch sw = new Stopwatch();
            sw.Start();
            //程序开始
             for (int i = 0; i < 1000000; i++)
            {
                x += i;
            }
            //程序结束
            sw.Stop();
            this.label1.Text += ",sum=" + x.ToString();
            MessageBox.Show(sw.ElapsedMilliseconds.ToString());
3.计算一个页面执行时间:
        在Global.asax.cs文件中增加以下代码:
         protected void Application_BeginRequest(Object sender, EventArgs e)
        {
            Application["StartTime"] = System.DateTime.Now;
        }
        protected void Application_EndRequest(Object sender, EventArgs e)
        {
            System.DateTime startTime = (System.DateTime)Application["StartTime"];
            System.DateTime endTime = System.DateTime.Now;
            System.TimeSpan ts = endTime - startTime;
            Response.Write("页面执行所用时间:" + ts.Milliseconds + " 毫秒");
        }