private void danhMụcXeMáyToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            frm_Xe xe = new frm_Xe();

            xe.ShowDialog();
        }
        private void btnDMXeMay_Click(object sender, EventArgs e)
        {
            this.Hide();
            frm_Xe tk = new frm_Xe();

            tk.ShowDialog();
        }