理解抽象工廠模式中的代碼

Question

我想在 C# 學習設計模式，我的朋友給我寫了一些抽象工廠模式的代碼（我認為）。

從我所看到的代碼創建一個工廠（Fa），這個工廠（Fa）然后創建另一個基於枚舉的工廠（Fb）然后那個工廠（Fb）創建一個具體的 class 可用於調用 API 等.

我可以創建一個工廠 (Fb) 並創建 class 但是當我從工廠 (fb) 創建的 class 調用方法時，我看不到我的方法並且無法調用它們但只能調用它繼承的 class .

簡而言之，我想做的是創建一個工廠來創建 Jane 娃娃（就像它所做的那樣），它繼承了娃娃 class 的所有內容，它也有自己的所有屬性，很好，但為什么我不能訪問它自己的屬性當我創建一個工廠來創建 Jane Factory 時，它只允許我以這種方式使用繼承的 Doll 方法，但如果我創建另一個工廠來創建聖誕老人玩偶，它就會有我需要使用的不同方法。

**網絡控制器**

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


namespace Qqq.Dolls.Web.Controllers
{

    public class InventoryController : Controller
    {
        private readonly IDollFactory _dollFactory;
        private readonly IJaneDollFactory _janeDollFactory;
        private readonly IMapper _mapper;

        public InventoryController(IJaneDollFactory dollFactory, IMapper mapper, IDollFactory dollFactory1)
        {
            _janeDollFactory = dollFactory;
            _mapper = mapper;
            _dollFactory = dollFactory1;
        }

        public async Task<IActionResult> List()
        {
            var token = HttpContext.Session.GetObject<OAuthResponse>(SessionConstants.JaneToken);
            var doll = _JaneDollFactory.Create(token, JaneScopeConstants.GetAllScopes());


            var a = _DollFactory.Create(Doll.Jane, HttpContext);

            var ab = await a.LGetProductAsync("TestProduct");


            var inventory = await doll.GetInventory();

            var ret = inventory.InventoryItems.Select(
                inventoryItem => _mapper.Map<InventoryViewModel>(inventoryItem));

            return View(ret);

        }
    }

}

人偶工廠

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Qqq.Dolls.Web.Infrastructure;

public class DollFactory : IDollFactory
{
    private readonly IJaneDollFactory _JaneDollFactory;

    public DollFactory(IJaneDollFactory JaneDollFactory)
    {
        _JaneDollFactory = JaneDollFactory;
    }

    public IDoll Create(Doll Doll, HttpContext httpContext)
    {
        switch (Doll)
        {
            case Doll.Jane:
                var token = httpContext.Session.GetObject<OAuthResponse>(SessionConstants.JaneToken);

                return _JaneDollFactory.Create(token, JaneScopeConstants.GetAllScopes());
            default:
                throw new NotImplementedException();
        }

    }
}

IJaneDollFactory 接口

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Qqq.Dolls.Jane;

public interface IJaneDollFactory
{
    IJaneDoll Create(OAuthResponse oAuthResponse, List<string> scopes, HttpMessageHandler httpMessageHandler = null);
}

**IJaneDoll 界面**

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Qqq.Dolls.Jane;

public interface IJaneDoll : IDoll
{
    //Inventory
    Task<Inventory> GetInventory();
    Task ListInventoryItem(InventoryItem product);
    Task DeleteInventoryItem(string sku);

}

玩偶界面

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

public interface IDoll
{
    Task ListProductAsync(Product product);

    Task<Product> GetProductAsync(string productId);
}

接口 IDollFactory

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Qqq.Dolls.Web.Infrastructure;

public interface IDollFactory
{
    IDoll Create(Doll doll, HttpContext httpContext);
}

簡娃娃工廠

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


namespace Qqq.Dolls.Jane;

public class JaneDollFactory : IJaneDollFactory
{
    private readonly IMapper _mapper;
    private readonly JaneApiConfiguration _JaneApiConfiguration;

    public JaneDollFactory(IOptions<JaneApiConfiguration> JaneApiConfiguration, IMapper mapper)
    {
        _mapper = mapper;
        _JaneApiConfiguration = JaneApiConfiguration.Value;
    }
    public IJaneDoll Create(OAuthResponse oAuthResponse, List<string> scopes, HttpMessageHandler httpMessageHandler = null)
    {
        return new JaneDoll(_mapper, _JaneApiConfiguration, oAuthResponse, scopes, httpMessageHandler);
    }

}

Answer 1

發生這種情況是因為在您的工廠創建方法中，您的返回類型為

偶像

所以當你創建一個娃娃時，無論你實例化什么娃娃，它都會被隱式地轉換成一個 IDoll（這是 DollFactory 類中的錯誤）

由於您的調用者知道它希望抽象工廠創建什么玩偶，因此當您檢索 object 時，您可以將其顯式轉換為 IJaneDoll

var a = (IJaneDoll) _DollFactory.Create(Doll.Jane, HttpContext);

這應該允許您訪問 IDoll 和 IJane doll 的成員。