private void btDonhang_Click(object sender, EventArgs e)
        {
            DonHang_Form frm = new DonHang_Form();

            frm.ShowDialog();
        }
 private void btDonhang_Click(object sender, EventArgs e)
 {
     DonHang_Form frm = new DonHang_Form();
     frm.ShowDialog();
 }