C#给文件重命名

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

using System.IO;
namespace ModifyFileName
{
    /// <summary>
    /// 为了修改从电驴上下载的电子书的名字而写的程序，不具有通用性。
    /// 例如：把  [2006IT类新书合集].Wiley_Telecom.For.Dummies(2006.4).chm 
    /// 改为  Wiley_Telecom.For.Dummies(2006.4).chm  也就是给它重命名。
    ///
    /// </summary>
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string path ;
            if (DialogResult .OK ==folderBrowserDialog1 .ShowDialog ())
            {
                path = folderBrowserDialog1.SelectedPath;
                string []files = Directory .GetFiles (path );
                foreach (string  var in files )
                {
                    if (var.Length > 22)
                    {
                        string substr = var.Substring(8, 14);
                        if (substr == "[2006IT类新书合集].")
                        {
                            //MessageBox.Show(var);
                            string filePath = var.Substring(0, 8) + var.Substring(22, var.Length - 22);
                            File.Move(var, filePath);
                        }                   
                    }

                }
            }
        }
    }
}