using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.IO;namespace WindowsFormsApplication5{    public partial class Form1 : Form    {        string filename;        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            OpenFileDialog dig = new OpenFileDialog();            if (dig.ShowDialog()==DialogResult.OK)                filename = dig.FileName;        }        private void button2_Click(object sender, EventArgs e)        {            SaveFileDialog dig = new SaveFileDialog();            if (dig.ShowDialog()==DialogResult.OK)                File.Copy(filename,dig.FileName);        }    }}