private void CmbDoctor_SelectedIndexChanged(object sender, EventArgs e) { if (cmbDoctor.SelectedItem != null) { int doctorId = ((User)(cmbDoctor.SelectedItem)).UserId; DateTime selectedDate = dtpAppointmentDate.Value.Date; DateTime selectedDate2 = dtpAppointmentDate.Value.Date.AddDays(1); hourController = new HourController(); hours = hourController.GetAll(); appointmentController = new AppointmentController(); var listHour = appointmentController.Hours(hours, doctorId, selectedDate, selectedDate2); if (listHour.Count > 0) { cmbHour.DataSource = listHour; cmbHour.DisplayMember = "HourInfo"; cmbHour.ValueMember = "HourId"; } } cmbHour.Text = string.Empty; }