private void methodConfirmation()
        {
            try
            {
                connection.Open();
                command.Connection = connection;
                string sqlConfirm = "SELECT userName, password FROM tblUser WHERE userName = @username AND password = @password";
                command.CommandText = sqlConfirm;
                command.Parameters.AddWithValue("@username", username);
                command.Parameters.AddWithValue("@password", txtPassword.Text);
                SqlDataReader reader = command.ExecuteReader();
                command.Parameters.Clear();
                if (reader.HasRows)
                {
                    connection.Close();
                    successful = "true";
                    this.Tag = successful;
                    this.Close();
                }
                else
                {
                    MessageBox.Show("Incorrect password.");
                    txtPassword.Focus();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error: " + ex);
            }
            finally
            {
                connection.Close();
            }
        }