private void cancelBtn_Click(object sender, EventArgs e)
        {
            this.Hide();
            AppointmentsListScreen appointmentsListScreen = new AppointmentsListScreen();

            appointmentsListScreen.Show();
        }
        private void saveBtn_Click(object sender, EventArgs e)
        {
            int      appointmentId      = Int32.Parse(appointmentIDTextBox.Text);
            int      customerId         = Int32.Parse(customerIDComboBox.Text);
            string   appointmentType    = appointmentTypeComboBox.Text;
            DateTime startTimeDateLocal = startDateTimePicker.Value;
            DateTime endTimeDateLocal   = endDateTimePicker.Value;



            DateTime startTimeUTC = TimeZoneInfo.ConvertTimeToUtc(startTimeDateLocal, TimeZoneInfo.Local);
            DateTime endTimeUTC   = TimeZoneInfo.ConvertTimeToUtc(endTimeDateLocal, TimeZoneInfo.Local);

            string startTimeUTCstring = startTimeUTC.ToString("yyyy-M-dd HH:mm:ss");
            string endTimeUTCstring   = endTimeUTC.ToString("yyyy-M-dd HH:mm:ss");


            try
            {
                appointmentType = getAppointmentType();
            }
            catch (AppointmentTypeException appointmentTypeException)
            {
                Console.WriteLine("\n" + appointmentTypeException.Message);
                return;
            }
            try
            {
                checkCustomerName();
            }
            catch (CustomerIDDoesNotMatchException customerIdDoesNotMatchException)
            {
                Console.WriteLine("\n" + customerIdDoesNotMatchException.Message);
                return;
            }
            try
            {
                if (outsideBusinessHoursCheck())
                {
                    ;
                }
            }
            catch (AppointmentSchedulingException outsideBusinessHoursException)
            {
                Console.WriteLine("\n" + outsideBusinessHoursException.Message);
                return;
            }
            try
            {
                if (!overLappingAppointmentsCheck())
                {
                    ;
                }
            }
            catch (AppointmentSchedulingException appointmentOverlappingException)
            {
                Console.WriteLine("\n" + appointmentOverlappingException.Message);
                return;
            }

            con.Open();

            string query = "insert into appointment values ( " + appointmentId + ", " + customerId + ", " + CurrentOnlineUser.currentOnlineUserID + ",  'not needed', 'not needed', 'not needed', 'not needed', '" + appointmentType + "',  'not needed', '" + startTimeUTCstring + "', '" + endTimeUTCstring + "', '" + DateTime.UtcNow.ToString("yyyy-M-dd HH:mm:ss") + "', '" + CurrentOnlineUser.currentOnlineUserName + "', '" + DateTime.UtcNow.ToString("yyyy-M-dd HH:mm:ss") + "',  '" + CurrentOnlineUser.currentOnlineUserName + "' )";

            MySqlDataReader row;

            row = con.ExecuteReader(query);


            con.Close();


            this.Hide();
            AppointmentsListScreen appointmentsListScreen = new AppointmentsListScreen();

            appointmentsListScreen.Show();
        }