C#文件复制小工具

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 copyFile
{
    public partial class Form1 : Form
    {
        String fileName;
        String folderName;
        String extendedName;
        String fileName1;
        
        public Form1()
        {
            InitializeComponent();
        }

        private void browse_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();                //new一个方法
            ofd.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);  //定义打开的默认文件夹位置
            ofd.ShowDialog();          //显示打开文件的窗口
             fileName = ofd.FileName;               //获得选择的文件路径
             textBox1.Text = fileName;
             extendedName = Path.GetExtension(fileName);       //获得文件扩展名
             fileName1 = Path.GetFileName(fileName);           //获得文件名
        }

        private void folder_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog fbd = new FolderBrowserDialog();
            fbd.ShowDialog();
            folderName = fbd.SelectedPath;                     //获得选择的文件夹路径
            textBox3.Text = folderName;
        }

        private void ok_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Trim().Length == 0)
            {
                MessageBox.Show("文件路径不能为空!");
                return;
            }
            if (textBox2.Text.Trim().Length == 0)
            {
                MessageBox.Show("复制数量不能为空!");
                return;
            }
            if (textBox3.Text.Trim().Length == 0)
            {
                MessageBox.Show("目标文件夹路径不能为空!");
                return;
            }
            String newFile;                   //定义存储的位置,和存储的名称
            
            for (int i = 1; i <= Convert.ToInt32(textBox2.Text); i++)                   //从textBox2中获取要复制的次数
            {
                newFile = folderName + "\\" + fileName1 +"_"+ i.ToString() + extendedName;
                File.Copy(fileName, newFile, true);            //使用Copy复制文件, Copy(源文件位置,目标文件夹位置,是否可以覆盖同名文件)
            }
            MessageBox.Show("复制完成!");
        }
    }
}

//获取文件名 
Path.GetFileName(OpenFileDialog.FileName) 

//获取文件路径 
Path.GetDirectoryName(OpenFileDialog.FileName) 

//获取文件扩展名 
Path.GetExtension(OpenFileDialog.FileName)