private void btnEditRoleUser_Click(object sender, EventArgs e)
        {
            OracleDataController.ConnectDB(FormLogin.connectionStr);
            string query = null;

            if (comboEditUserInfor.SelectedIndex != -1)
            {
                if (comboOldRole.Items.Count > 0)
                {
                    query = "revoke " + comboOldRole.Text + " from " + comboEditUserInfor.SelectedItem.ToString();
                    bool checkIsRevoke = OracleDataController.Revoke(query);
                    if (checkIsRevoke)
                    {
                        MessageBox.Show("Revoke role successfully!");
                    }
                }

                query = "grant " + comboEditNewRole.SelectedItem.ToString() + " to " + comboEditUserInfor.SelectedItem.ToString();
                bool checkIsGrant = OracleDataController.Grant(query);
                if (checkIsGrant)
                {
                    MessageBox.Show("Grant role successfully!");
                }
            }
        }