private void btnDespachar_Click(object sender, EventArgs e)
{
int descontar = Convert.ToInt32(objetoCD.funcDesc(Convert.ToInt32(cbProductos.SelectedValue.ToString()))) - Convert.ToInt32(txtCantidad.Text);
objetoCD.Despachar(descontar, Convert.ToInt32(cbProductos.SelectedValue.ToString()));
dataGridView1.DataSource = objetoCD.Mostrar();
}