private void BtnPrint_Click(object sender, EventArgs e)
{
Dictionary <int, Orden> temp = new Dictionary <int, Orden>();
foreach (DataGridViewRow r in DGVOrden.SelectedRows)
{
temp.Add((int)r.Cells[0].Value, ordenes[(int)r.Cells[0].Value]);
}
Impresora printer = new Impresora();
printer.ContruirVistaPrevia(temp);
}