using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

namespace fileIO

{

    class Program

    {

        static void Main(string[] args)

        {

            string filename =AppDomain.CurrentDomain.BaseDirectory+ "companyUpdateLog.txt";

            if (File.Exists(filename))

            {

                string time=ReadLog(filename);

                if (time != "") {

                    DateTime dt;

                    if (DateTime.TryParse(time, out dt)) {

                        DateTime dtnow = DateTime.Now;

                        int days = (dtnow - dt).Days;

                        if (days == 7)

                        {

                            //开始更新

                            Console.WriteLine("正在更新");

                            WriteLog(filename, dtnow.ToString("yyyy-MM-dd HH:mm:ss"));

                        }

                        else {

                            Console.WriteLine("无需更新");

                        }

                    }

                }

            }

            else {

                DateTime dtnow = DateTime.Now;

                //开始更新

                Console.WriteLine("文件不存在时候：正在更新");

                WriteLog(filename, dtnow.ToString("yyyy-MM-dd HH:mm:ss"));

            }

            Console.ReadLine();

        }

      public static  void WriteLog(string path,string text) {

          using (FileStream file = new FileStream(path, FileMode.OpenOrCreate))

            {

                StreamWriter sw = new StreamWriter(file);

                sw.Write(text);

                sw.Close();

            }

        }

      public static string ReadLog(string path)

      {

          string a="";

          using (FileStream file = new FileStream(path, FileMode.Open))

          {

              StreamReader sw = new StreamReader(file);

              a=sw.ReadToEnd();

              sw.Close();

          }

          return a;

      }