private void btnAgregar_Click(object sender, EventArgs e)
        {
            frmAlta alta = new frmAlta();

            alta.ShowDialog();
            cargar();
        }
        private void btnModificar_Click(object sender, EventArgs e)
        {
            Articulo Art;

            Art = (Articulo)dgvlista.CurrentRow.DataBoundItem;
            frmAlta modificar = new frmAlta(Art);

            modificar.ShowDialog();
            cargar();
        }