如何在Controller中使用依赖注入

Question

我有下面的代码,可以没有任何问题 MAUserController.cs

public class MAUserController : ApiController
    {
        ILogService loggerService;
        IMAUserService _service;

        public MAUserController(ILogService loggerService, IMAUserService Service)
        {
            this.loggerService = loggerService;
            this._service = Service;
        }
}

DependencyInstaller.cs

public class DependencyInstaller : IWindsorInstaller
    {
        public void Install(IWindsorContainer container, IConfigurationStore store)
        {
            container.Register(
                Component.For<ILogService>().ImplementedBy<LogService>().LifeStyle.PerWebRequest,
                Component.For<IDatabaseFactory>().ImplementedBy<DatabaseFactory>().LifeStyle.PerWebRequest,
                Component.For<IUnitOfWork>().ImplementedBy<UnitOfWork>().LifeStyle.PerWebRequest,
                AllTypes.FromThisAssembly().BasedOn<IHttpController>().LifestyleTransient(),
                AllTypes.FromAssemblyNamed("ISOS.Health.Service").Where(type => type.Name.EndsWith("Service")).WithServiceAllInterfaces().LifestylePerWebRequest(),
                AllTypes.FromAssemblyNamed("ISOS.Health.Repository").Where(type => type.Name.EndsWith("Repository")).WithServiceAllInterfaces().LifestylePerWebRequest()               
                );
        }
    }

如果我使用普通的控制器而不是ApiController,那么它会给我一个错误 UserController.cs

public class UserController : Controller
    {
        ILogService loggerService;
        IMAUserService _service;
        public UserController(ILogService loggerService, IMAUserService Service)
        {
            this.loggerService = loggerService;
            this._service = Service;
        }
}

这会产生错误:

没有为此对象定义的无参数构造函数

我使用CastleDI Windsor进行依赖注入.

我需要做任何事情或注册一些东西吗？

Answer 1

第一种方法

建议:谨慎使用,因为它可能会导致Castle Windsor的内存泄漏.

您必须创建一个控制器激活器,它应该实现该IControllerActivator接口,以便使用您的DI容器来创建控制器实例:

public class MyWindsorControllerActivator : IControllerActivator
{
    public MyWindsorControllerActivator(IWindsorContainer container)
    {
        _container = container;
    }

    private IWindsorContainer _container;

    public IController Create(RequestContext requestContext, Type controllerType)
    {
        return _container.Resolve(controllerType) as IController;
    }
}

然后,将此类添加到您的DependencyInstaller:

public class DependencyInstaller : IWindsorInstaller
{
    public void Install(IWindsorContainer container, IConfigurationStore store)
    {
        container.Register(
                // Current code...

                Component.For<IControllerActivator>()
                    .ImplementedBy<MyWindsorControllerActivator>()
                    .DependsOn(Dependency.OnValue("container", container))
                    .LifestyleSingleton();
            );
    }
}

另外,根据Windsor容器创建自己的依赖项解析器:

public class MyWindsorDependencyResolver : IDependencyResolver
{
    public MyWindsorDependencyResolver(IWindsorContainer container)
    {
        _container = container;
    }

    private IWindsorContainer _container;

    public object GetService(Type serviceType)
    {
        return _container.Resolve(serviceType);
    }

    public IEnumerable<object> GetServices(Type serviceType)
    {
        return _container.ResolveAll(serviceType).Cast<object>();
    }
}

然后,最后,Application_Start在Global.asax.cs 中的方法中注册依赖项解析器:

DependencyResolver.SetResolver(new MyWindsorDependencyResolver(windsorContainer));

这样,当MVC需要控制器激活器通过它的依赖解析器时,它将获得我们的,它将使用我们的Windsor容器来创建具有所有依赖性的控制器.

为了避免使用内存泄漏IControllerActivator,最简单的解决方案是使用每个线程或每个Web请求的生活方式,而不是注册组件的默认(Singleton),transient和pooled.有关如何使用Castle Windsor Container避免内存泄漏的详细信息,请查看此链接.

第二种方法

然而,正如@PhilDegenhardt所指出的,更好更正确的方法是实现自定义控制器工厂,以便能够释放由Castle Windsor DI Container创建的控制器组件.在这里您可以找到一个示例(请参阅有关依赖注入的部分).

从该示例中可以看出,实现可能是:

的Global.asax.cs:

public class MvcApplication : System.Web.HttpApplication
{
    private WindsorContainer _windsorContainer;

    protected void Application_Start()
    {
        var _windsorContainer = new WindsorContainer();
        _windsorContainer.Install(
            new DependencyInstaller(),
            // Other installers...
        );

        ControllerBuilder.Current.SetControllerFactory(new WindsorControllerFactory(_windsorContainer.Kernel));
    }

    protected void Application_End()
    {
        if (_windsorContainer != null)
        {
            _windsorContainer.Dispose();
        }
    }
}

WindsorControllerFactory.cs:

public class WindsorControllerFactory : DefaultControllerFactory
{
    private readonly IKernel _kernel;

    public WindsorControllerFactory(IKernel kernel)
    {
        _kernel = kernel;
    }

    public override void ReleaseController(IController controller)
    {
        _kernel.ReleaseComponent(controller);  // The important part: release the component
    }

    protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        if (controllerType == null)
        {
            throw new HttpException(404, string.Format("The controller for path '{0}' could not be found.", requestContext.HttpContext.Request.Path));
        }
        return (IController)_kernel.Resolve(controllerType);
    }
}