Question

I’ve gone through quite a few articles on the repository pattern and had some questions.
I’m trying to implement this in a ASP.NET 4.0 application.
The architecture is a layered architecture with a Presentation Layer, Business Layer and Data Layer.
From this article, http://www.primaryobjects.com/CMS/Article108.aspx

I have created the MYSQLRepository (DataLayer)

public class MySQLRepository:IOrderRepository
{
    public List<Order> GetOrders()
    {

        List<Order> orders = new List<Order>();
        orders.Add(new Order(1,"A"));
        orders.Add(new Order(2,"B"));

        return orders;
    }
}

My Business Layer looks like this

public class OrderBL
{
    IOrderRepository orderrep;
    public OrderBL(IOrderRepository repository)
    {
       orderrep = repository;

    }

    public List<Order> GetOrders()
    {
        return orderrep.GetOrders();

    }
}

Now my question is that in the presentation layer, I’m expected to do this

protected void Page_Load(object sender, EventArgs e)
{
    OrderBL orderBL = new OrderBL(new MySQLRepository());
    List<Order> orders = orderBL.GetOrders();

    foreach (Order order in orders)
    {
        Response.Write(order.OrderId.ToString() + ". " + order.OrderNo + "<br>");
    }

}

In order to do this, I have to reference my DataLayer in the presentation layer. Isn’t that wrong? Ideally I would only want to reference my Business Layer.
IS something wrong in my implementation or is it not the right place to implement the pattern. I have seen many examples using ASP.NET MVC and it seems to work well there.

Also, Do i really need dependency injection here?

Thanks for the help
Soni

Answer 1

it’s better to unilize IoC to get constructor injection, this will remove unnecessary layers’ references.