private void btnSua_Click(object sender, EventArgs e)
{
frmTonDauKy fm = new frmTonDauKy(mamathang, ngaycapnhat, soluong, giatriton);
fm.FormClosed += Fm_FormClosed;
fm.ShowDialog();
}
private void btnThem_Click(object sender, EventArgs e)
{
frmTonDauKy fm = new frmTonDauKy();
fm.FormClosed += Fm_FormClosed;
fm.ShowDialog();
}