private void btnPrescriptonAdd_Click(object sender, EventArgs e)
        {
            string drugs = string.Empty;

            foreach (var item in lstDrugs.Items)
            {
                drugs += item + ",";
            }
            Prescription prescription = new Prescription
            {
                PatientId        = 2,
                PrescriptionDate = DateTime.Now,
                Drugs            = drugs
            };
            var result = prescriptionManagement.AddPrescription(prescription);

            lstDrugs.Items.Clear();
        }