c# 控制台应用程序批量修改文件夹下的后缀名(包括子文件夹)

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);
        }
    }
}

引用命名空间：using System.IO;