Three times wrong login credentials then login form will exit

In this blog we will know if a user provides three times wrong login credentials then the login form will be closed.

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.Data.OleDb;

namespace Invalid_login_three_times

{

public partial class Form1 : Form

{

string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];

OleDbCommand com;

OleDbDataAdapter oledbda;

DataSet ds;

DataTable dt;

string str;

string s1;

int Counter=0;

int i = 0;

int j = 0;

public Form1()

{

InitializeComponent();

}

private void btn_login_Click(object sender, EventArgs e)

{

if ((txt_userid.Text == "") && (txt_password.Text==""))

{

MessageBox.Show("Userid and Password cannot be blank");

txt_userid.Focus();

return;

}

Counter = Counter + 1;

if ((Counter < 3))

{

j = dt.Rows.Count - 1;

for (i = 0; i <= j; i++)

{

if ((txt_userid.Text == dt.Rows[i].ItemArray[0].ToString() & txt_password.Text == dt.Rows[i].ItemArray[1].ToString()))

{

MessageBox.Show("Userid and Password are correct");

this.Close();

}

else

{

s1 = Convert.ToString(3 - Counter);

}

MessageBox.Show("Userid or Password are incorrect! You have " + s1 + " tries left.");

}

else

{

MessageBox.Show("Userid or Password are incorrect! You have no attempts left");

Application.Exit();

}

clear();

}

void clear()

{

txt_userid.Text = "";

txt_password.Text = "";

}

private void Form1_Load(object sender, EventArgs e)

{

OleDbConnection con = new OleDbConnection(ConnectionString);

try

{

con.Open();

str = "select * from login";

com = new OleDbCommand(str, con);

oledbda = new OleDbDataAdapter(com);

ds = new DataSet();

oledbda.Fill(ds, "login");

con.Close();

dt = ds.Tables["login"];

}

catch (Exception ex)

{

MessageBox.Show(ex.Message);

}

Thanks for reading