private void btnDanToc_Click(object sender, EventArgs e)
        {
            frmDanToc frm = new frmDanToc();

            frm.Show();
            this.Hide();
        }
        private void quảnLýDânTộcToolStripMenuItem_Click(object sender, EventArgs e)
        {
            frmDanToc frm = new frmDanToc();

            frm.Show();
            this.Hide();
        }