private void btnThemPhieuKham_Click(object sender, EventArgs e)
        {
            if (dgvDanhSachBenhNhan.SelectedRows.Count > 0)
            {
                DataGridViewRow row = dgvDanhSachBenhNhan.SelectedRows[0];

                BenhNhan          benhNhan = listBenhNhan.Single(p => p.MaBN == (int)row.Cells[0].Value);
                fAddEditPhieuKham f        = new fAddEditPhieuKham("Thêm phiếu khám", benhNhan, nhanVien.MaNV);
                f.ShowDialog();
                if (f.DialogResult == DialogResult.OK)
                {
                    listPhieuKham = libraryService.DanhSachPhieuKhamGUI(DateTime.Now);
                    LoadPhieuKham(listPhieuKham);
                    tabControl1.SelectTab(1);
                }
            }
        }
 private void btnCapNhatPhieuKham_Click(object sender, EventArgs e)
 {
     if (dgvDanhSachKham.SelectedRows.Count != 0)
     {
         DataGridViewRow row = dgvDanhSachKham.SelectedRows[0];
         //MessageBox.Show(row.Cells[2].Value.ToString());
         PhieuKhamGUI      phieuKham = listPhieuKham.Single(p => p.MaPhieuKham == (int)row.Cells[2].Value);
         BenhNhan          benhNhan  = listBenhNhan.Single(p => p.MaBN == (int)row.Cells[1].Value);
         fAddEditPhieuKham f         = new fAddEditPhieuKham("Cập nhật phiếu khám", phieuKham, benhNhan);
         f.ShowDialog();
         if (f.DialogResult == DialogResult.OK)
         {
             listPhieuKham = libraryService.DanhSachPhieuKhamGUI(DateTime.Now);
             LoadPhieuKham(listPhieuKham);
         }
     }
 }