private void btnNL_Click(object sender, EventArgs e)
        {
            FormNguyenLieu f = new FormNguyenLieu();

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

            f.ShowDialog();
        }