private void thôngTinTàiKhoảnToolStripMenuItem_Click(object sender, EventArgs e)
 {
     tt = new ThongTinNhanVien(s);
     tt.Show();
 }
 private void navBarItem3_LinkClicked(object sender, DevExpress.XtraNavBar.NavBarLinkEventArgs e)
 {
     tt = new ThongTinNhanVien(s);
     tt.Show();
 }