Simple MD5Sum Generator Used for Warm and Synergy Updater

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.Security.Cryptography;
using System.IO;

namespace WarmMD5Sum
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // Get current application directory path
            string executableName = Application.ExecutablePath;
            FileInfo executableFileInfo = new FileInfo(executableName);
            string executableDirectoryName = executableFileInfo.DirectoryName;

            // Process the list of zip files found in directory where this program is running
            string[] fileEntries = Directory.GetFiles(executableDirectoryName, "*.zip");

            string filesProcessed = "Files Processed:" + Environment.NewLine + Environment.NewLine;

            foreach (string fileName in fileEntries)
            {
                // Generate MD5Sum from file
                byte[] b = System.IO.File.ReadAllBytes(fileName);
                string sum = BitConverter.ToString(new MD5CryptoServiceProvider().ComputeHash(b)).Replace("-", "").ToLower();

                // Create MD5Sum file  
                string MD5SumOutputFile = fileName + ".MD5Sum";
                TextWriter tw = new StreamWriter(MD5SumOutputFile);
                tw.WriteLine(sum);
                tw.Close(); 
               
                // Record what files were processed
                filesProcessed += fileName + Environment.NewLine + Environment.NewLine;
            }

            MessageBox.Show(filesProcessed);

        }
    }
}