Step 5: Solution with a Service class

Add the Core, the Data project references to the Service project

Add interface IWishlistService to the Core project

public interface IWishlistService
{ 
   void AddWishlistItem(string description, int quantity); 
   IList<WishListItem> GetAllWishlistItems();
}

Add class WishlistService to to the Service project

public class WishlistService : IWishlistService
{ 
  readonly IUnitOfWork _unitOfWork; 
  public WishlistService(IUnitOfWork unitOfWork) 
  {  
     _unitOfWork = unitOfWork; 
  } 
  public void AddWishlistItem(string description, int quantity) 
  {  
      var wishListItem = new WishListItem  
      {   
            Description = description,   Quantity = quantity  
      };  
      using (_unitOfWork)  
      {   
         _unitOfWork.WishListItemRepository.Insert(wishListItem);   
         _unitOfWork.Save();  
      } 
  } 
  public IList<WishListItem> GetAllWishlistItems() 
  {  
     using (_unitOfWork)  
     {   
       return (List<WishListItem>)_unitOfWork.WishListItemRepository.GetAll();  
     }
  }
}

You can find the solution on GitHub.

https://github.com/sunilrav/Wishlist.5.SolutionWithService