private void btnNhapHang_Click(object sender, EventArgs e)
 {
     frmNhapHang f = new frmNhapHang();
     f.Show();
 }
        private void btnNhapHang_Click(object sender, EventArgs e)
        {
            frmNhapHang f = new frmNhapHang();

            f.Show();
        }