class association

问题:

I am working on a program that is supposed to simulate bank accounts. I have my base class called "Investment", my two subclasses called "Stock" and "MutualFund", and I also have a class called "CustomerAccount" that is supposed to be associated with the base class "Investment".

I'm not sure how to associate the CustomerAccount class with the Investment class.

回答1:

The CustomerAccount class has a "CanHave" relationship with Investment.

In your CustomerAccount class, create a collection of Investments. You could use a list to achieve this:

List<Investment> _investments;

Don't forget to initialize the list in your constructor.

_investments = new List<Investment>();

Edit:

Looping through the list:

foreach Investment invst in _investments
{
    if (invst.GetType() == typeof(Stock)) { }
    else if (invst.GetType() == typeof(MutualFund)) { }
}

回答2:

Rather than having an account have AddStock and AddMutualFund it should just have AddInvestment which is then used to add either a stock or an inventment. You then get all Investments, rather than getting all stocks or mutual funds.