Line number

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 WindowsFormsApplication1

{

    public partial class linenumber : Form

    {

        public linenumber()

        {

            InitializeComponent();

        }

        private void openToolStripMenuItem_Click(object sender, EventArgs e)

        {

            openFileDialog1.Filter = "Text file(*.txt)|*.txt";

            string filename;

            if (openFileDialog1.ShowDialog() == DialogResult.OK)

            {

                filename = openFileDialog1.FileName;

                int dr = 0;

                FileStream f = new FileStream(filename, FileMode.Open);

                StreamReader sr = new StreamReader(f);

                string line;

                StreamWriter sw = File.CreateText(@"E:\numbered.txt");

                while ((line = sr.ReadLine()) != null)

                {

                    dr++;

                    sw.WriteLine("{0}{1}", dr, line);

                }

                sw.Close();

                f.Close();

                MessageBox.Show("File numbered successfully");

                System.Diagnostics.Process.Start(@"E:\numbered.txt");

            }

        }

    }

}