For example if I say I have three classes A, B, and C where B and C have a composition relation ship with A. That means the life of B and C is handled by A, and also B and C cannot access directly from the outside.

For some reason my DataService class needs to return objects of B and C as It cant return a object of A as B and C cannot be initialized at the same time. (to be able to initializeC you have to initializeB first).

So that I'm returning DataTables from DataService and then inside the class A those data tables are converted to B / C objects.

1. If B and C objects cannot be initialized at the same time is it valid to say that B and C have a composition relationship with A?

2. If its composition is it must to generate A with B and C inside?

3. What is the proper way to handle this sort of a problem?

EDIT:

Following code explains the way I'm doing it now with DataTables.

Example:

class A   
{  
    private List<B> B;
    private List <C> C;

    public A()
    {
        B= new List<B>();
        C= new List<C>();
    }

    public List<B> GetB( DataTable dt) 
    {
        // Create a B list from dt
        return B;
    }
}


class Presenter
{
  private void Show B()
  {
    _View.DataGrid = A.GetB(DataService.GetAListOfB());
  }
}

The actual scenario is I have a class called WageInfo and classes Earning and Deduction having a composition relationship in the design. But for you to generate Deductions first you should Generate earnings and should be saved in a table. Then only you can generate deductions for the earnings to calculate balance wages.

Also note that these contained classes have a one to many relationship with the containing class WageInfo. So actually WageInfo has a List<Earnings> and List<Deduction>

My initial question was, is it ok if my DataService class returns Deductions / Earnings objects (actually lists) not a WageInfo?

Still not clear?