private void deleteToolStripMenuItem_Click(object sender, EventArgs e) { if (patientsListView.SelectedItems.Count > 0) { int patientId = int.Parse(patientsListView.SelectedItems[0].Tag.ToString()); Patient patient = patientManager.GetPatientById(patientId); PatientDiseaseManager patientDiseaseManager = new PatientDiseaseManager(); patientDiseaseManager.DeleteExisting(patient); if (patientManager.DeleteByPatientId(patientId)) { Close(); MessageBox.Show("Patient Successfully Deleted"); } else { MessageBox.Show("An Error Occured"); } } else { MessageBox.Show("You must Select a row"); } }