using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApplication2

{

    class Program

    {

        static void Main(string[] args)

        {

            DirectoryInfo theFolder = new DirectoryInfo("E:\\620000S00000_20160707\\");  // 目录文件位置 

            FileInfo[] fileInfo = theFolder.GetFiles(); // 获得当前的文件夹内的所有文件数组

            int i = ;

            foreach (FileInfo NextFile in fileInfo)   //遍历文件

            {

                if (NextFile.Extension == ".db")  // 得到你想要的格式

                {

                    string dbName = NextFile.Name;

                    string name = dbName.Replace(".db", "");

                    Log("");

                    Log("============"+i+":  " + name + "==============");

                    UpdateName(name);

                    i++;

                }

            }

           Log("批量修改成功");

            Console.ReadLine();

        }

        public static void UpdateName(string dname)

        {

            //批量更改文件名

            string path1 = @"E:\ContDB\" + dname;

            DirectoryInfo di = new DirectoryInfo(path1);//此处写你的文件目录地址

            if (!File.Exists(path1))

            {

                foreach (FileInfo fi in di.GetFiles("*.txt"))//举例：可以用 di.GetFiles("*.jpg") 只重名jpg文件

                {

                    //逐个修改文件后缀

                    String FileName = fi.Name;

                    Console.WriteLine(FileName);//输出文件名称

                    string getExtension = Path.GetExtension(FileName);

                    Console.WriteLine("扩展名：{0}", getExtension);

                    string newFileName = FileName.Replace(getExtension, ".csv");

                    Console.WriteLine("更改后：{0}", newFileName);

                    string newDirectoryName = Path.Combine(path1, newFileName);

                    fi.MoveTo(newDirectoryName);//必须有这步

                }

            }

        }

        static void Log(string s)

        {

            Console.WriteLine("" + s);

        }

    }

}