private void btnVentas_Click(object sender, EventArgs e)
        {
            Pantalla_Venta formVenta = new Pantalla_Venta();

            formVenta.Show();
            this.Hide();
        }
        private void btnCancelar_Click(object sender, EventArgs e)
        {
            Pantalla_Venta formMenu = new Pantalla_Venta();

            formMenu.Show();
            this.Close();
        }