public override bool Delete(Guid id)
{
if (id == Guid.Empty)
{
throw new ArgumentException("invoice id cannot be empty");
}
var invoice = Persistor.Get(id);
// verify that the invoice dosen't have any payments
// we can't delete invoices that have payments
if (invoice.Payments != null && invoice.Payments.Count > 0)
{
throw new NotImplementedException("an invoice that contains a payment can not be deleted");
}
Persistor.Delete(id);
return(Persistor.Commit() > 0);
}