private void btChitiet_Click(object sender, EventArgs e)
{
FormHoaDon hd = new FormHoaDon(lb_Tongtien.Text, txtIDhd.Text);
//this.Hide();
hd.Show();
}
private void btnHoadon_Click(object sender, EventArgs e)
{
FormHoaDon f2 = new FormHoaDon();
f2.Show();
}