private void quảnLýHàngHóaToolStripMenuItem_Click(object sender, EventArgs e)
        {
            frm_QLSanPham frmsp = new frm_QLSanPham();

            frmsp.Activate();
            frmsp.ShowDialog();
        }
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            frm_QLSanPham frmsp = new frm_QLSanPham();

            frmsp.Activate();
            frmsp.ShowDialog();
        }