private void trangChủToolStripMenuItem_Click(object sender, EventArgs e)
 {
     GUI.Intro it = new Intro();
     it.MdiParent   = this;
     it.WindowState = FormWindowState.Maximized;
     it.Show();
 }
        private void frmMain_Load(object sender, EventArgs e)
        {
            timer1.Enabled = true;
            GUI.Intro it = new Intro();
            it.MdiParent   = this;
            it.WindowState = FormWindowState.Maximized;
            it.Show();

            lblTen.Text = "Chào bạn: " + DTO.ConnectDatabase.NameLogin;
        }