Object Oriented Approach for C#

Question

Hi there

I am exploring this and see if this one make sense. For instance I have 2 abstract objects called: Customer and Tender. The relationship is that Customer can have many Tenders.

My question is how to achieve like this on the TestClient app:

1) customer.InTender[0].ID = ???

What method to handle to handle this? Do I need to pass CustomerID into Customer constructor to achieve this or ... ?

2) If I want to get all tenders for that particular customer should I do this:

customer.InTender.Get()

3) HOw do I differentiate between All Tender VS All Customer Tender (point 3). I guess it will be like this. One with ID of CUstomer and the other one without?

inTender.Get()

I appreciate your feedback.

===========================================

public abstract class Customer
{
    protected Int64 id;
    protected string name;

    protected ArrayList tender;

    public abstract ArrayList Tender
    {
       get;
       set;
    }  

    public abstract Int64 ID
    {
       get;
       set;
    }  

    public abstract string Name
    {
       get;
       set;
    }  


    public abstract bool Update();

    public abstract bool Add();

    public abstract bool Delete();
}

public class CorporateCustomer : Customer
{
    public CorporateCustomer ()
    {}

        public override ArrayList Tender
        {
            get
            {
                return tender
            }
            set
            {
                tender = value;
            }
        }   

    public override Int64 ID
        {
            get
            {
                return id;
            }
            set
            {
                id = value;
            }
        }

        public override string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
            }
        }

    public override bool Update()
    {
    return true;
    }

    public override bool Add()
    {
    return true;
    }

    public override bool Delete()
    {
    return true;
    }
}


public abstract class Tender
{
    protected Int64 id;
    protected string name;

    public abstract bool Update();

    public abstract bool Add();

    public abstract bool Delete();

}

public class InTender : Tender
{
    public InTender ()
    {}


    public override Int64 ID
        {
            get
            {
                return id;
            }
            set
            {
                id = value;
            }
        }

        public override string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
            }
        }

    public override bool Update()
    {
    return true;
    }

    public override bool Add()
    {
    return true;
    }

    public override bool Delete()
    {
    return true;
    }
}

Answer 1

1) Don't use ArrayList, it was depreciated as of .net 2.0. You should use List, IList, or Dictionary.

Also, Customer sure seems like concrete type. Are you going to have multiple Customer classes that all inherit from it? If not, drop the Abstract. Same goes for your other classes.

2) Look up Repository objects and LazyLoading. Davy Bryon has a good series on building your own DAL. http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/

But either the customer should have all of the Tenders right away, or you should have a service that gets them for you. I'm not in favor of having Entities know about their persistence.

Anyway, the general approach is to have a separate Repository class that has the methods needed to get the data you need.

public class CustomerRepository
{
    public List<Customer> GetAllCustomers() { .... }
    public List<Tenders> GetTendersForCustomer(Customer customer) { .... }

}

Answer 2

I think a standard Tender class and a standard Customer class with a property List < Tender > should suffice. I don't see why you need the abstract classes and the inheritance.

class Tender {}

class Customer { List < Tender > tenders; // would be null if customer has no tenders .... }