.Net Core Dependency Injection 从构造函数中注入

问题描述

我需要从构造函数中注入我在 Setup 中声明的所有内容.

I need to inject out of constructor, everything I declared in Setup.

我能做到吗?如何从构造函数中注入服务?类似于 Angular 2 中的 Injector 服务.

Ho can I do it ? How can I inject services out of constructor ? Something like Injector service in Angular 2.

在控制器中没有构造函数的情况下注入服务

类似的东西

    public class ControllerBase : Controller
    {
        protected IRepository<Test> _test;
        protected IRepository<Test1> _test1;
        protected IRepository<Test2> _test2;

        public ControllerBase(INJECTOR injector)
        {
            _test = injector.inject(IRepository<Test>);
            _test1 = injector.inject(IRepository<Test1>);
            _test2 = injector.inject(IRepository<Test2>);
        }
    }

    public class SomeController : ControllerBase
    {
        public SomeController(INJECTOR injector)
            : base(injector)
        {

        }
    }

感谢@Rick van den Bosch 的回答

对于那些仍然无法得到我想要的东西的人:

public class ControllerBase : Controller
{
    protected IRepository<Test> _test;
    protected IRepository<Test1> _test1;
    protected IRepository<Test2> _test2;

    public ControllerBase(IServiceProvider injector)
    {
        _test = injector.GetService<IRepository<Test>>();
        _test1 = injector.GetService<IRepository<Test1>>();
        _test2 = injector.GetService<IRepository<Test2>>();
    }
}

public class SomeController : ControllerBase
{
    public SomeController(IServiceProvider injector)
        : base(injector)
    {
        //HERE I HAVE ALL 3 REPO NOW WITHOUT EXTRA LINES
    }
}
public class SomeController1 : ControllerBase
{
    public SomeController1(IServiceProvider injector)
        : base(injector)
    {
        //HERE I HAVE ALL 3 REPO NOW WITHOUT EXTRA LINES
    }
}

推荐答案

您可以将服务作为参数注入到操作方法中.这是通过使用属性 [FromServices] 标记参数来完成的.

You can inject the service as a parameter to the action method. This is done by marking the parameter with the attribute [FromServices].

这看起来像这样:

public IActionResult About([FromServices] IDateProvider dateProvider)
{
    ViewData["Message"] = $"Current date is {dateProvider.CurrentDate}";

    return View();
}

如果您正在寻找 BaseController 中的默认服务:您可以通过以下几种方式进行:

If you're looking for default services in a BaseController: you could go about that several ways:

1.仍然使用构造函数
这看起来像这样:

1. Still use a constructor
This would look something like this:

public class HomeController : BaseController
{
    public HomeController(IDateProvider dateProvider) : base(dateProvider)
    {
    }
}

和

public class BaseController
{
    protected IDateProvider _dateProvider;

    protected BaseController(IDateProvider dateProvider)
    {
        _dateProvider = dateProvider;
    }
}

这样 IDateProvider 对 BaseController 和所有继承的 Controller 都可用.

This way the IDateProvider is available to both the BaseController and all inheriting Controllers.

<强>2.手动解析服务
这样您就可以手动解析服务.这可能在 BaseController 中，并且仅在您需要它们时(懒惰).有关详细信息，请参阅这篇文章.

为了简单和可读性，我可能会选择构造函数.

For simplicity and readability I would probably choose the constructor one.

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