private void listView1_MouseClick(object sender, MouseEventArgs e)
{
lblSoLuongGioHang.Visible = false;
btnGioHang.Visible = false;
panel6.Visible = true;
string tentailieu = listView1.SelectedItems[0].SubItems[0].Text.ToString();
TaiLieu tl = new TaiLieu();
txtCTTL.TextName = tl.loadMaChiTietTaiLieu(tentailieu);
txtTenTL.TextName = tentailieu;
txtNXB.TextName = tl.loadtennxb(tentailieu);
txtTacGia.TextName = tl.loadtacgia(tentailieu);
txtViTri.TextName = tl.loadvitri(tentailieu);
txtTheLoai.TextName = tl.loadtheloai(tentailieu);
txtSoLuong.TextName = tl.loadsoluongtailieu(tentailieu);
txtGiaBia.TextName = tl.loadgiabia(tentailieu);;
txtNCC.TextName = tl.loadncc(tentailieu);
anhQR.Image = byteArrayToImage(tl.loadAnhQR(tentailieu));
}