Change all file names in specific folder

The code to do that will be something like this:

using System;

using System.IO;

class Program

{

static void Main()

{

string[] folderPaths = {"c:\\NumberFolder1\\Folder2", "c:\\NumberFolder1\\folder3"};

foreach(string folderPath in folderPaths) ChangeFileNames(folderPath);

}

static void ChangeFileNames(string folderPath)

{

string[] filePaths = Directory.GetFiles(folderPath, "*.xls");

foreach(string filePath in filePaths)

{

string fileName = Path.GetFileName(filePath);

string folderName = Path.GetDirectoryName(filePath);

fileName = "Number_" + fileName;

File.Move(filePath, String.Format("{0}\\{1}", folderName, fileName));

}