private void button1_Click(object sender, EventArgs e) { string username = txtTaiKhoan.Text; string password = txtMatKhauMoi.Text; LoginDB db = new LoginDB(); try { if (db.ChangePassword(username, password)) { MessageBox.Show("Thay doi thanh cong"); } }catch (Exception ex) { MessageBox.Show("Thay doi mat khau that bai"); } }