代码验证C#执行”文件打开关闭操作“耗时

2017-04-19

部门经理习惯用C#做数据清洗，遇到个需要验证的问题，在一个万次左右循环内对文件执行打开关闭操作，比在循环前打开文件、循环后关闭文件耗时多多少。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Diagnostics;
using System.Threading;

namespace ConsoleApplication1
{
    public class Program
    {
        static void Main(string[] args)
        {
            int index = ;
            long i = ;
            var stopWatch = new Stopwatch();
            //StreamWriter f = new StreamWriter(@"D:\sum.txt", false);
            for (i = ; i < ; i++)
            {
                stopWatch.Start();
                if (i == )
                {
                    stopWatch.Stop();
                    Console.WriteLine("Program run" + stopWatch.ElapsedMilliseconds + "ms.");
                    Thread.Sleep();
                }
                i += ;
                Console.WriteLine(i);
                StreamWriter f = new StreamWriter(@"D:\sum.txt", false);
                index += ;
                f.Write(index);
                f.Close();
            }
            //f.Close();
            Console.ReadKey();
        }
    }
}