我发布了this review不久前在 codereview.stackexchange.com 上...我觉得它可能更适合 stackoverflow，因为它更多的是一个问题而不是代码审查。
需要一些解释，请耐心等待。
<小时/>我正在 ASP.NET MVC 中开发一个电子商务网站。用户可以在网站上发布不同类型的广告。
我使用继承来定义我的广告类型，这个问题是关于利用分层结构删除 Controller 和 View 中的重复代码。
我有不同的广告类型:SimpleAd , Car和RealEstateRental .
每个广告都源自 AdBase，它具有所有共同属性:
public abstract class AdBase
{
public long AdBaseId { get; set; }
public bool IsActive { get; set; }
public long UserId { get; set; }
public string Title { get; set; }
public short AdDurationInDays { get; set; }
public string PhotosFolder { get; set; }
}
现在其他广告均从此基类派生:
public class SimpleAd : AdBase
{
public decimal Price { get; set; }
}
public class Car : AdBase
{
public decimal Price { get; set; }
public string Make { get; set; }
}
public class RealEstateRental : AdBase
{
public decimal WeeklyRent { get; set; }
public DateTime AvailableFrom { get; set; }
public short NoOfBedrooms { get; set; }
public short NoOfBathrooms { get; set; }
}
我正在使用 Entity Framework 与数据库交互，并且我正在使用工作单元和存储库模式:
我有一个通用的 AdBaseRepository，其中包含所有常见的广告方法:
public abstract class AdBaseRepository<TEntity> where TEntity : AdBase
{
protected readonly ApplicationDbContext Context;
public AdBaseRepository(ApplicationDbContext context)
{
Context = context;
}
public TEntity Get(long adBaseId)
{
return Context.AdBase.OfType<TEntity>()
.Where(r => r.IsActive == true && r.AdBaseId == adBaseId)
.FirstOrDefault();
}
// more common methods here...
}
其他广告存储库继承自上述类:
public class SimpleAdRepository : AdBaseRepository<SimpleAd>
{
public SimpleAdRepository(ApplicationDbContext context) : base(context)
{
}
}
public class CarRepository : AdBaseRepository<Car>
{
public CarRepository(ApplicationDbContext context) : base(context)
{
}
// methods which apply only to car here...
}
这是我的工作单元:
public class UnitOfWork
{
protected readonly ApplicationDbContext Context;
public UnitOfWork(ApplicationDbContext context)
{
Context = context;
SimpleAd = new SimpleAdRepository(Context);
RealEstateRental = new RealEstateRentalRepository(Context);
Car = new CarRepository(Context);
}
public SimpleAdRepository SimpleAd { get; private set; }
public RealEstateRentalRepository RealEstateRental { get; private set; }
public CarRepository Car { get; private set; }
public int SaveChanges()
{
return Context.SaveChanges();
}
public void Dispose()
{
Context.Dispose();
}
}
到目前为止，我对一切都很满意...但问题是我不知道如何在 Controller 和 View 中利用这种继承层次结构。
目前，我有 3 个 Controller :SimpleAdController , CarController和RealEstateRentalController :
public class SimpleAdController : ControllerBase
{
private UnitOfWork _unitOfWork;
public SimpleAdController(UnitOfWork unitOfWork)
{
_unitOfWork = unitOfWork;
}
[HttpGet]
// display specific ad
public ActionResult Display(long id)
{
SimpleAd simpleAd = _unitOfWork.SimpleAd.Get(id);
/*
* I have not included my ViewModel Classes in this question to keep
* it small, but the ViewModels follow the same inheritance pattern
*/
var simpleAdDetailsViewModel = Mapper.Map<SimpleAdDetailsViewModel>(simpleAd);
return View(simpleAdDetailsViewModel);
}
}
CarController和RealEstateRentalController有相同的Display方法，除了广告的类型不同(例如在 CarController 我有):
public ActionResult Display(long id)
{
Car car = _unitOfWork.Car.Get(id);
var carViewModel = Mapper.Map<CarViewModel>(car);
return View(car);
}
我想要实现的是创建一个 AdBaseController将所有常用方法放入其中，如下所示:
public class AdBaseController : ControllerBase
{
private UnitOfWork _unitOfWork;
public AdBaseController(UnitOfWork unitOfWork)
{
_unitOfWork = unitOfWork;
}
// Display for generic ad type
[HttpGet]
public ActionResult Display(long id)
{
// SimpleAd simpleAd = _unitOfWork.SimpleAd.Get(id);
/*
* I need to replace the above line with a generic ad type...
* something like: _unitOfWork<TAd>.GenericAdRepository.Get(id)
*/
// var simpleAdDetailsViewModel = Mapper.Map<SimpleAdDetailsViewModel>(simpleAd);
// return View(simpleAdDetailsViewModel);
/*
* similarly I have to replace the above 2 lines with a generic type
*/
}
}
如果我执行上述操作，那么我的广告 Controller 可以继承它，并且我不需要在每个 Controller 中重复相同的显示方法...但随后我需要创建我的 UnitOfWork通用...或有 2 个 UoW(通用和非通用)...我不确定这是否是一个好主意？ 关于 AdBaseController 的任何建议？
同样，我在 View 中重复了很多代码。例如，这是显示SimpleAdView :
<div class="row">
<div class="col-l">
@*this partial view shows Ad photos and is common code for all ad types*@
@Html.Partial("DisplayAd/_Photos", Model)
</div>
<div class="col-r">
<div class="form-row">
@*Common in all ads*@
<h5>@Model.Title</h5>
</div>
@*showing ad specific fields here*@
<div class="form-row">
<h5 class="price">$@Model.Price</h5>
</div>
@*Ad heading is common among all ad types*@
@Html.Partial("DisplayAd/_AdBaseHeading", Model)
</div>
</div>
@*Ad Description is common among all ad types*@
@Html.Partial("DisplayAd/_Description", Model)
这是我的显示器 CarView :
<div class="row">
<div class="col-l">
@*Common in all ads*@
@Html.Partial("DisplayAd/_Photos", Model)
</div>
<div class="col-r">
<div class="form-row">
@*Common in all ads*@
<h5>@Model.Title</h5>
</div>
@*Price and Make are specific to Car*@
<div class="form-row">
<h5 class="price">$@Model.Price</h5>
</div>
<div class="form-row">
<h5 class="make">@Model.Make</h5>
</div>
@*Common in all ads*@
@Html.Partial("DisplayAd/_AdBaseHeading", Model)
</div>
</div>
@*Common in all ads*@
@Html.Partial("DisplayAd/_Description", Model)
我再次感觉我在每个 View 中重复了很多代码。我尝试通过将重复代码放入公共(public)部分 View 中来减少重复代码的数量。 我不确定是否有更好的方法来做到这一点？
最佳答案
从技术上来说这是可能的。对于类似的实体，您可以引入枚举并使用它来指示您在 Controller 中处理的实体类型。您可以创建通用 View 来处理类似的广告(但当然，您需要根据模型广告类型显示/隐藏相应的 UI 元素)。这是 Controller 的伪代码来说明这个想法:
using System.Threading.Tasks;
using AutoMapper;
using MyNamespace.Data;
using Microsoft.AspNetCore.Mvc;
using MyNamespace.ViewModels;
namespace MyNamespace
{
public enum AdType
{
[Description("Simple Ad")]
SimpleAd = 0,
[Description("Car")]
Car = 1,
[Description("Real Estate Rental")]
RealEstateRental = 2
}
public class AdController : Controller
{
private readonly ApplicationDbContext _context;
private readonly IMapper _mapper;
public AdController(
ApplicationDbContext context,
IMapper mapper)
{
_context = context;
_mapper = mapper;
}
[HttpGet("Ad/{type}")]
public IActionResult Index(AdType? type = AdType.SimpleAd)
{
switch (type)
{
case AdType.RealEstateRental:
return RedirectToAction("RealEstateRental");
case AdType.Car:
return RedirectToAction("Car");
case AdType.SimpleAd:
default:
return RedirectToAction("SimpleAd");
}
}
[HttpGet("Ad/Car")]
public IActionResult Car()
{
return View("Index", AdType.Car);
}
[HttpGet("Ad/RealEstateRental")]
public IActionResult RealEstateRental()
{
return View("Index", AdType.RealEstateRental);
}
[HttpGet("Ad/SimpleAd")]
public IActionResult SimpleAd()
{
return View("Index", AdType.SimpleAd);
}
[HttpGet("Ad/List/{type}")]
public async Task<IActionResult> List(AdType type)
{
// var list = ... switch to retrieve list of ads via switch and generic data access methods
return list;
}
[HttpGet("Ad/{type}/Details/{id}")]
public async Task<IActionResult> Details(AdType type, int id)
{
var ad = // ... switch by type to retrieve list of ads via switch and generic data access methods
if (ad == null) return NotFound($"Ad not found.");
// for instance - configure mappings via Automapper from DB entity to model views
var model = _mapper.Map<AdViewModel>(ad);
// Note: view will have to detect the exact ad instance type and show/hide corresponding UI fields
return View(model);
}
[HttpGet("Ad/{type}/Add/")]
public IActionResult Add(AdType type)
{
var ad = // ... switch by type to validate/add new entity
return View(_mapper.Map<AdEditModel>(ad));
}
[HttpPost("Ad/{type}/Add/")]
public async Task<IActionResult> Add(AdEditModel model)
{
// detect ad type and save
return View(model);
}
[HttpGet("Ad/{type}/Edit/{id}")]
public async Task<IActionResult> Edit(AdType type, int id)
{
// similar to Add
return View(model);
}
[HttpPost("Ad/{type}/Edit/{id}")]
public async Task<IActionResult> Edit(AdEditModel model)
{
// similar to Add
return View(model);
}
// And so on
}
}
但我应该注意，UI 相关代码中的继承最终会导致更多的问题而不是好处。代码变得更加复杂，难以维护并保持干净。因此，将所有 Views 和 Controllers 分开更有意义，即使它们的代码非常接近。您可以开始优化 DI 服务(又名业务逻辑)或类似层下的“重复代码”使用。
UI级别的重复代码问题应该通过提取组件来解决(又名控件、部分 View 、 View 组件)。 Controller 继承是可能的，但会使代码更难维护。
关于asp.net-mvc - 利用 Controller 和 View 中的继承，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52284912/