ArgumentNullException in WindsorControllerActivator

Question

我有一个具有多层(程序集)的项目。我使用城堡温莎解决依赖注入问题。还可以用城堡创建我的控制器。因此，我也在WebUI和WebUI层中安装和使用了城堡。此外，我还有一个引导程序层，它注册了所有服务和存储库。

首先我的web：

在WebApiConfig.cs文件中，我用流动的代码注册了UI依赖项：

public static void Register(HttpConfiguration config)
    {

        var corsAttr = new EnableCorsAttribute("*", "*", "*");
        config.EnableCors(corsAttr);

        // Web API configuration and services
        var container = Bootstrapper.WireUp();// to register services and repositories
        RegisterControllers(container);
        config.Services.Replace(typeof(IHttpControllerActivator), new WindsorControllerActivator(container));

    }

    private static void RegisterControllers(IWindsorContainer container)
    {
        //container.Register(Component.For<VisitorController>().LifestylePerWebRequest());
        //container.Register(Component.For<ValueController>().LifestylePerWebRequest());
        //container.Register(Component.For<ValidateController>().LifestylePerWebRequest());
        //container.Register(Component.For<CaptchaImageController>().LifestylePerWebRequest());
        container.Register(Classes.FromAssemblyContaining<VisitorController>()
            .BasedOn<ApiController>().LifestyleTransient());
    }

活化剂工厂是这样的：

 public class WindsorControllerActivator : IHttpControllerActivator
{
    private readonly IWindsorContainer _container;
    public WindsorControllerActivator(IWindsorContainer container)
    {
        _container = container;
    }

    public IHttpController Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
    {
        return (IHttpController)_container.Resolve(controllerType);//System.ArgumentNullException: Value cannot be null. error
    }
}

在WebUI项目中，我还使用城堡温莎来创建控制器。但是当我运行该项目时，我得到的"System.ArgumentNullException:值不能为null.“当我正在解析控制器时出错，我的意思是在这一行：

(IHttpController)_container.Resolve(controllerType);

我还为我的控制器尝试了"LifeStylePerWebRequest“，没有任何改变。

更重要的是，WireUp方法没有什么问题(注册服务和存储库很好)。这个问题仅适用于控制器(在WebUI和WebApi项目中)。WebUI项目也会出现同样的问题。

Answer 1

我通常使用IDependencyResolver的实现而不是IHttpControllerActivator。你可以用这种方法代替。添加浮动级：

public class WindsorDependencyResolver : IDependencyResolver
{
    readonly IWindsorContainer _container;

    public WindsorDependencyResolver(IWindsorContainer container)
    {
        if (container == null)
        {
            throw new ArgumentNullException(nameof(container));
        }

        _container = container;
    }

    public IDependencyScope BeginScope()
    {
        return new WindsorDependencyScope(this, _container.Release);
    }

    public void Dispose()
    {
    }

    public object GetService(Type t)
    {
        var ret = _container.Kernel.HasComponent(t) ? _container.Resolve(t) : null;
        return ret;
    }

    public IEnumerable<object> GetServices(Type t)
    {
        var ret = _container.ResolveAll(t).Cast<object>().ToArray();
        return ret;
    }
}

依赖项解析器需要此类：

public class WindsorDependencyScope : IDependencyScope
    {
        readonly List<object> _instances;
        readonly Action<object> _release;
        readonly IDependencyScope _scope;

        public WindsorDependencyScope(IDependencyScope scope, Action<object> release)
        {
            if (scope == null)
            {
                throw new ArgumentNullException(nameof(scope));
            }

            if (release == null)
            {
                throw new ArgumentNullException(nameof(release));
            }

            _scope = scope;
            _release = release;
            _instances = new List<object>();
        }

        public void Dispose()
        {
            foreach (object instance in _instances)
            {
                _release(instance);
            }

            _instances.Clear();
        }

        public object GetService(Type t)
        {
            var service = _scope.GetService(t);
            AddToScope(service);

            return service;
        }

        public IEnumerable<object> GetServices(Type t)
        {
            var services = _scope.GetServices(t);
            AddToScope(services);

            return services;
        }

        void AddToScope(params object[] services)
        {
            if (services.Any())
            {
                _instances.AddRange(services);
            }
        }
    }

这就是如何在Register方法中注册依赖项解析器：

config.DependencyResolver = new WindsorDependencyResolver(container);

我建议在依赖解析器负责处理这些控制器时，使用瞬态的生活方式注册控制器。