BaseController 的重载构造函数没有被执行？

Question

public class BaseController : Controller
{
    [Inject]
    public IUnitOfWork UnitOfWork { get; set; }
    private readonly ISomeService _someService ;

    public BaseController(ISomeService someService)
    {
        _someService = someService;
    }

    public void Contacts()
    {
        contacts = _someService .GetById(1);
        ViewBag.someThing = contacts; //Add whatever
    }

    public BaseController()
    {

    }
}

当我在 :base 中发送 someService 时，我可以从中获取数据。但是我不想从每个控制器发送 someService 就像 AboutController 到 BaseController 并写太多代码。

public class HomeController : BaseController
{

    private readonly ISomeService someService;

    public HomeController(ISomeService someService) : base(someService)
    {
        _someService = someService;
    }
}

public class AboutController : BaseController
{
    private readonly IAboutService _aboutService;
    public AboutController (IAboutService aboutService) 
    {
        _aboutService = aboutService;
    }
}

所以在 AboutController 视图中我仍然想获取一些服务的数据而不向 BaseController 发送参数

Answer 1

简答题分两种情况：

如果您想从基本控制器使用 ISomeService，您必须像这样通过基本构造函数传递该服务：

public class AboutController : BaseController
{
     private readonly IAboutService _aboutService;
     public AboutController (IAboutService aboutService, ISomeService someService)  : base(someService)
     {
         _aboutService = aboutService;
     }
}

如果您不想使用该服务，您可以像这样使用默认的基本构造函数，否则如果您尝试访问它，它将为空：

public class AboutController : BaseController
{
   private readonly IAboutService _aboutService;
   public AboutController (IAboutService aboutService)  : base()
   {
       _aboutService = aboutService;
    }
}

您属于第一种情况，需要通过构造函数传递给它进行初始化！

但是如果您想打破这种模式，您可以选择其他方式将服务注入到您的基本控制器中：

第一个使用自动属性：

例如：

public ISomeService SomeService { get; set;}

另一种方法是使用 DependecyResolver 获取服务实例，但这会 'break' 以某种方式成为 DI 模式，并且会使测试等变得更加困难。但是如果您选择这样做这是代码：

  public class BaseController : Controller
  {
     [Inject]
     public IUnitOfWork UnitOfWork { get; set; }
     private readonly ISomeService _someService ;

     public BaseController(ISomeService someService)
     {
         _someService = someService;
     }

     public void Contacts()
     {
         contacts = _someService .GetById(1);
         ViewBag.someThing = contacts; //Add whatever
     }

     public BaseController()
     {
          _someService = DependencyResolver.Current.GetService<ISomeService >();
     }
}

有关更多信息，请参阅此问题 here

BaseController 的重载构造函数没有被执行？

BaseController's overloaded constructor not being executed?

c#

dependency-injection

repository

unit-of-work

asp.net-mvc-5