private void BtnDelete_Click(object sender, EventArgs e)
{
//int.Parse(cmbMedicine.SelectedValue.ToString().Substring(0, 4).Trim());
int id = int.Parse(cmbMedicine.SelectedValue.ToString().Substring(0, 2).Trim());
pharmacy.DeleteMedicines(id);
cmbMedicine.DataSource = null;
cmbMedicine.DataSource = pharmacy.GetMedicines();
dgv.DataSource = null;
dgv.DataSource = pharmacy.GetMedicines();
}