private void button1_Click(object sender, EventArgs e) { try { //Define object of SqlConnection and paasing of ConnectioString copied from database property SqlConnection conn = new SqlConnection(); //conn.ConnectionString = @"Data Source=SAGAR-C2F6419CA;Initial Catalog=info;Integrated Security=True"; conn.ConnectionString = @"Data Source=HIREN-9CF1490E8;Initial Catalog=Medical;Integrated Security=True"; //Connection with Database starts conn.Open(); //Create object of SqlAdapter and pass the query and object of ConnectionString SqlDataAdapter adptr = new SqlDataAdapter("SELECT * FROM Login", conn); //Create object of Dataset DataSet ds = new DataSet(); //dataset is fiiled with dataAdapter adptr.Fill(ds); //create object of DataTable and assign the table to it DataTable dt = ds.Tables[0]; //loops start Boolean b = false; for (int i = 0; i < dt.Rows.Count; i++) { //comparision with the username and password entered if ((textBox1.Text).Equals((dt.Rows[i][0]).ToString()) && (textBox2.Text).Equals((dt.Rows[i][1]).ToString())) { MessageBox.Show("You Are Successfully Loged in...", "Wel-Come To Medical-Store-Management-System", MessageBoxButtons.OK, MessageBoxIcon.None); //shows the mdi form and hide the login form Mdi_parent1 childMdi = new Mdi_parent1(); childMdi.Show(); this.Hide(); b = true; break; } } // if User name and password are not matched if (!b) { MessageBox.Show("Invalid Username and Password", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); textBox1.Text = ""; textBox2.Text = ""; textBox1.Focus(); } // Closing of database conn.Close(); } finally { } }