C# Kayıt Programı

Kod:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Configuration;
using MySql.Data.MySqlClient;
using System.Data.SqlClient;

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

        private void button3_Click(object sender, EventArgs e)
        {  
            baglantı.aç
            StreamWriter ahm = File.AppendText("csdosyaislemleri.txt");
            ahm.WriteLine(textBox1.Text + "$" + textBox2.Text + "$" + textBox3.Text);
            ahm.Flush();
            ahm.Close();
            int i = 0;
            
            try
            {
                using (streamReader sr = new Stream())
                    Reader("text.txt");
                {
                    string line;
                    while ((line = sr.Readline()) != null)
                    {
                        listBox1.Items.Add(line);
                    }
                }
            }
            catch
            {
                MessageBox.Show("Hata Meydana Geldi");
            }
            but++;
        }

    }
}