c# - .Net Core 2.0 中 Controller 和 BaseController 中的依赖注入(inject)重复

Question

如果我在我的 Asp.Net Core 2.0 Web 应用程序中创建一个 BaseController 来封装一些常见的依赖项，它们在实际 Controller 中是否仍然是必需的。

例如，默认 MVC 6 网络应用程序中的标准帐户和管理 Controller 。

public class AccountController : Controller
{
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly SignInManager<ApplicationUser> _signInManager;
    private readonly IEmailSender _emailSender;
    private readonly ILogger _logger;

    public AccountController(
        UserManager<ApplicationUser> userManager,
        SignInManager<ApplicationUser> signInManager,
        IEmailSender emailSender,
        ILogger<AccountController> logger)
    {
        _userManager = userManager;
        _signInManager = signInManager;
        _emailSender = emailSender;
        _logger = logger;
    }
   //rest of code removed
}

public class ManageController : Controller
{
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly SignInManager<ApplicationUser> _signInManager;
    private readonly IEmailSender _emailSender;
    private readonly ILogger _logger;
    private readonly UrlEncoder _urlEncoder;

    private const string AuthenicatorUriFormat = "otpauth://totp/{0}:{1}?secret={2}&issuer={0}&digits=6";

    public ManageController(
      UserManager<ApplicationUser> userManager,
      SignInManager<ApplicationUser> signInManager,
      IEmailSender emailSender,
      ILogger<ManageController> logger,
      UrlEncoder urlEncoder)
    {
        _userManager = userManager;
        _signInManager = signInManager;
        _emailSender = emailSender;
        _logger = logger;
        _urlEncoder = urlEncoder;
    }
    // rest of code removed
}

在我正在构建的自定义 Web 应用程序模板中，我将帐户 Controller 重构为三个不同的 Controller ，RegisterController(它处理与用户注册有关的所有事情)、LoginController(它处理登录和注销)，以及平衡到第三个。我将管理 Controller 一分为二，一个 ManagePasswordController(与密码相关的所有内容)和一个 UserManageController(所有其他内容)。

每个的 DI 要求有很多共性，我想将它们放在一个 BaseController 中。看起来像这样？

public abstract class BaseController : Controller
{
    private readonly IConfiguration _config;
    private readonly IEmailSender _emailSender;
    private readonly ILogger _logger;
    private readonly SignInManager<ApplicationUser> _signInManager;
    private readonly UserManager<ApplicationUser> _userManager;

     protected BaseController(IConfiguration iconfiguration,
        UserManager<ApplicationUser> userManager,
        SignInManager<ApplicationUser> signInManager,
        IEmailSender emailSender,
        ILogger<ManageController> logger)
    {
        _config = iconfiguration;
        _userManager = userManager;
        _signInManager = signInManager;
        _emailSender = emailSender;
        _logger = logger;
    }
    //rest of code removed
}

但是好像什么都没做？因为在我看来我仍然必须注入(inject)一切。我不可能是对的(我是 DI 的新手，所以显然不知道)但是 BaseController 应该允许我做 NO DI，这在 BaseController 和 RegisterController 之间很常见。我错了吗？我如何完成我想做的事情？

public class RegisterController : BaseController
{
    private const string ConfirmedRegistration = "User created a new account with password.";

    private readonly UserManager<ApplicationUser> _userManager;
    private readonly SignInManager<ApplicationUser> _signInManager;
    private readonly IEmailSender _emailSender;
    private readonly ILogger _logger;
    private readonly IConfiguration _config;

     public RegisterController(
        IConfiguration config,
        UserManager<ApplicationUser> userManager,
        SignInManager<ApplicationUser> signInManager,
        IEmailSender emailSender,
        ILogger<AccountController> logger) : base(config, userManager, signInManager, emailSender, logger)

    {
        _userManager = userManager;
        _signInManager = signInManager;
        _emailSender = emailSender;
        _logger = logger;
        _config = config;
    }
    //rest of code removed
}

更新

根据 Rufo 爵士的建议

public abstract class BaseController : Controller
{
    protected UserManager<ApplicationUser> UserManager { get; }
    protected SignInManager<ApplicationUser> SignInManager { get; }
    protected IConfiguration Config { get; }
    protected IEmailSender EmailSender { get; }
    protected ILogger AppLogger { get; }

    protected BaseController(IConfiguration iconfiguration,
        UserManager<ApplicationUser> userManager,
        SignInManager<ApplicationUser> signInManager,
        IEmailSender emailSender,
        ILogger<ManageController> logger)
    {
        AppLogger = logger;
        EmailSender = emailSender;
        Config = iconfiguration;
        SignInManager = signInManager;
        UserManager = userManager; 
    }
}

和继承 Controller

public class TestBaseController : BaseController
{

    public TestBaseController() : base()
    {

    }
}

这行不通。 Resharper 告诉我必须将参数添加到 TestBaseController 构造函数中的基本构造函数调用。

在.Net Core 2.0 中，BaseController 是否应该继承自Controller 或ControllerBase？

Answer 1

Microsoft.AspNetCore.MVC.Controller类自带扩展方法

HttpContext.RequestServices.GetService<T>

只要 HttpContext 在管道中可用，就可以使用它(例如，如果从 Controller 的构造函数调用，HttpContext 属性将为 Null)

试试这个模式

注意:确保包含此指令使用 Microsoft.Extensions.DependencyInjection；

基础 Controller

public abstract class BaseController<T> : Controller where T: BaseController<T>
{

    private ILogger<T> _logger;

    protected ILogger<T> Logger => _logger ?? (_logger = HttpContext.RequestServices.GetService<ILogger<T>>());

子 Controller

[Route("api/authors")]
public class AuthorsController : BaseController<AuthorsController>
{

    public AuthorsController(IAuthorRepository authorRepository)
    {
        _authorRepository = authorRepository;
    }

    [HttpGet("LogMessage")]
    public IActionResult LogMessage(string message)
    {
        Logger.LogInformation(message);

        return Ok($"The following message has been logged: '{message}'");
    }

不用说了，记得在Startup.cs中注册你的服务-->ConfingureServices方法