Question

I have a situation in a service method where assigning a POCO as a child object of another POCO does not work as expected. I am using Entity Framework 4.

public void ChangeOrderCurrency(Currency currency)  
{
    order.CurrencyId = currency.Id;
    order.Currency = currency;
    // other stuff related to exchange rates etc
}

Which is more correct to use to set the relationship? order.CurrencyId = currency.Id or order.Currency = currency?

In this current code which passes all unit tests, occasionally the line order.Currency = currency will set both order.CurrencyId and order.Currency to NULL

Answer 1

It makes more sense to use the currency object, not just the Id because when you retrieve data you will most likely want to have the Currency property and not just the Id. When you create / update you will have the Id available in both scenarios.