try
            {
                if (i == 2)
                {
                    Application.Exit();
                }
                conn.Open();
                string query = "select password from users where username = @usr and password = @pas";
                MySqlCommand cmd = new MySqlCommand(query, conn);
                cmd.Parameters.AddWithValue("@usr", username);
                cmd.Parameters.AddWithValue("@pas", password);
                MySqlDataReader myreader;
                myreader = cmd.ExecuteReader();
                string rez = (string)myreader.ToString();
                if (rez == password.Text)
                {
                    frmMain mainF = new frmMain();
                    mainF.Show();


                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Username or password is incorrect!");
                i++;
            }

cmd.Parameters.AddWithValue("@pas", password);

if (rez == password.Text)

cmd.Parameters.AddWithValue("@pas", password.Text);

cmd.Parameters.AddWithValue("@usr", username.Text);