Right-click on the solution item and select Add | New Project.... Add a class library project with the name NorthwindLogic.

Add a project reference to NorthwindDAL and NorthwindBDO to this new project.

Rename the Class1.cs file to ProductLogic.cs. This will also change the class name and all related places in the project.

Add the following two using statements to the ProductLogic.cs class file:

using NorthwindDAL;
using NorthwindBDO;

Add the following class member variable to the ProductLogic class:

ProductDAO productDAO = new ProductDAO();

Add the following new method, GetProduct, to the ProductLogic class:

public ProductBDO GetProduct(int id)
{
    return productDAO.GetProduct(id);
}

Add the following new method, UpdateProduct, to the ProductLogic class:

public bool UpdateProduct...