Dependency injection 没有使用依赖项解析程序为此对象定义无参数构造函数

我目前正在youtube上关注“asp net mvc 5教程上的依赖注入”

我照他说的做了，但我犯了这个错误

我的控制器是UnityDemoController

public class UnityDemoController : Controller
{

    private readonly ILocalWeaherServiceProvider _localWeaherServiceProvider;

    public UnityDemoController(ILocalWeaherServiceProvider localWeaherServiceProvider)
    {
        _localWeaherServiceProvider = localWeaherServiceProvider;

    }

    //
    // GET: /UnityDemo/

    public ActionResult Index()
    {


        string currentWeatherInMyArea = _localWeaherServiceProvider.GetLocalWeatherByZipCode("0006");

        return View();
    }

}

public class LocalWeatherServiceProvider : ILocalWeaherServiceProvider
{
    public string GetLocalWeatherByZipCode(string zipcode)
    {
        return "Its is snowing right now in your Area : " + zipcode;
    }
}

IocConfiguration.cs此配置位于App\u Start文件夹下

public static class IocConfiguration
{
    public static void ConfigureIocUnityContaioner()
    {
        IUnityContainer container = new UnityContainer();

        RegisterServices(container);

        DependencyResolver.SetResolver(new MyUnityDependancyResolver(container));
    }

    private static void RegisterServices(IUnityContainer container)
    {
        container.RegisterType<ILocalWeaherServiceProvider, LocalWeatherServiceProvider>(); // This means when somebody call/need ILocalWeaherServiceProvider then provide new Instance of the LocalWeatherServiceProvider


    }
}

服务类别LocalWeatherServiceProvider

public class UnityDemoController : Controller
{

    private readonly ILocalWeaherServiceProvider _localWeaherServiceProvider;

    public UnityDemoController(ILocalWeaherServiceProvider localWeaherServiceProvider)
    {
        _localWeaherServiceProvider = localWeaherServiceProvider;

    }

    //
    // GET: /UnityDemo/

    public ActionResult Index()
    {


        string currentWeatherInMyArea = _localWeaherServiceProvider.GetLocalWeatherByZipCode("0006");

        return View();
    }

}

public class LocalWeatherServiceProvider : ILocalWeaherServiceProvider
{
    public string GetLocalWeatherByZipCode(string zipcode)
    {
        return "Its is snowing right now in your Area : " + zipcode;
    }
}

我增加了团结

有人能告诉我这里出了什么问题吗？

---

避免这些类型的错误我应该研究这些编码级别的哪些方面？

我通过参考下面的链接找到了解决方案

更改UnityDemoController类，如下所示

public class UnityDemoController : Controller
{

    private readonly ILocalWeaherServiceProvider _localWeaherServiceProvider;

    public UnityDemoController() : this(new LocalWeatherServiceProvider())
    {

    }

    public UnityDemoController(ILocalWeaherServiceProvider localWeaherServiceProvider)
    {
        _localWeaherServiceProvider = localWeaherServiceProvider;
    }

    //
    // GET: /UnityDemo/

    public ActionResult Index()
    {
        string currentWeatherInMyArea = _localWeaherServiceProvider.GetLocalWeatherByZipCode("0006");

        return View();
    }

}

---

您是否正在使用

IOC配置

？在来自

IocConfiguration

的RegisterServices中放置一个断点，并在

MyUnityDependencyResolver

的GetServices中放置一个断点。在GetService/s的两个断点上，您可能希望添加一个条件，仅当类位于某个程序集中时才中断。一旦它在那里，再次运行它，让我知道你遇到了什么。谢谢你回答我的问题。当我使用条件或不使用条件设置上述断点时，IocConfiguration类中的RegisterServices不会达到调试点：（嘿，Tipx，我找到了解决方案。我在UnityDemoConroller中设置了默认结构，如下所示。

公共UnityDemoController（）：这个（新的LocalWeatherServiceProvider（））{}

从下面的链接[link]找到了它好的，太好了！@M.P.K.迪尔山：如果你找到了一个解决方案，请写下你的问题的答案并接受你的答案。如果你只写一条评论，它看起来像是一个未回答的问题。