private void SetButtonColor()
        {
            List<String> appointmentDates = new List<String>();
            appointmentDates.AddRange(appointmentService.getAppointmentsByDocAndDate(SelectedDate, DoctorId));

            if (appointmentDates.Count<1)
            {
                for (int i = 0; i < buttons.Count; i++)
                {
                    buttons[i].BackColor = System.Drawing.Color.Green;
                }
            }
            else
            {
                for (int i = 0; i < buttons.Count; i++)
                {
                    int e = 0;
                    Boolean found = false;
                    while (e < appointmentDates.Count && found == false)
                    {
                        if (appointmentDates[e].Equals(buttons[i].Text))
                        {
                            buttons[i].BackColor = System.Drawing.Color.Red;
                            found = true;
                        }

                        else
                        {
                            buttons[i].BackColor = System.Drawing.Color.Green;
                            e++;
                        }
                    }
                }
            }
        }