使用 Ninject，您如何根据绑定指定不同的生命周期？

Question

在我们的 MVC 应用程序中，我们主要使用 Ninject 将依赖项注入控制器。因此，我们的默认生命周期范围是 InRequestScope()。我们现在添加了一个 IHttpModule，它使用公共依赖项作为控制器（即 UserService）。问题是 HttpModules 可以由 ASP.NET 和 IIS 合并并在多个请求中重复使用。由于注入的依赖项设置为 InRequestScope，因此后续请求在 HttpModule 内部引用注入的依赖项时，通常会得到 ObjectDisposedException。如何在注入控制器时为 UserService 指定 InRequestScope() ，在注入 HttpModule 时如何指定 InScope() 。

这是我们注册的简化版本：

public static class NinjectWebCommon
{
    private static readonly Bootstrapper bootstrapper = new Bootstrapper();

    public static void Start(){
        DynamicModuleUtility.RegisterModule(typeof(OnePerRequestHttpModule));
        DynamicModuleUtility.RegisterModule(typeof(NinjectHttpModule));
        bootstrapper.Initialize(CreateKernel);
    }

    public static void Stop(){
        bootstrapper.ShutDown();
    }

    private static IKernel CreateKernel(){
        var kernel = new StandardKernel();
        kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);
        kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();
        kernel.Bind<IHttpModule>().To<CustomModule>(); // needs a UserService
        kernel.Bind<IUserService>().To<UserService>().InRequestScope(); // injected into controllers and the CustomModule
        DependencyResolver.SetResolver(new Services.NinjectDependencyResolver(kernel));
        return kernel;
    }
}

Answer 1

查看 .When() 绑定语法。您可以使用它来指定特定情况下服务的特定范围。这是一个例子：

class Program
{
    static void Main(string[] args)
    {
        var kernel = new StandardKernel();

        var scope1 = new object();
        var scope2 = new object();

        kernel.Bind<IWidget>().To<WidgetA>().InScope(c => scope1);
        kernel.Bind<IWidget>().To<WidgetA>().WhenInjectedInto<WidgetController>().InScope(c => scope2);

        var service = kernel.Get<GeneralWidgetService>();
        service.Print();

        service = kernel.Get<GeneralWidgetService>();
        service.Print();

        var controller = kernel.Get<WidgetController>();
        controller.Print();

        controller = kernel.Get<WidgetController>();
        controller.Print();

        // when scope2 changes, WidgetController gets a new widget, while WidgetService continues getting the existing widget
        scope2 = new object();

        service = kernel.Get<GeneralWidgetService>();
        service.Print();

        controller = kernel.Get<WidgetController>();
        controller.Print();
    }
}

public class WidgetController
{
    private readonly IWidget _widget;

    public WidgetController(IWidget widget)
    {
        _widget = widget;
    }

    public void Print()
    {
        Console.WriteLine("WidgetController ID: " + _widget.ID);
    }

}

public class GeneralWidgetService
{
    private readonly IWidget _widget;

    public GeneralWidgetService(IWidget widget)
    {
        _widget = widget;
    }

    public void Print()
    {
        Console.WriteLine("GeneralWidgetService ID: " + _widget.ID);
    }

}


public interface IWidget
{
    string ID { get; }
    string Name { get; }
}

public class WidgetA : IWidget
{
    private readonly string _id = Guid.NewGuid().ToString();

    public string ID { get { return _id; } }
    public string Name { get { return "AAAAAAAAAAAAAAAAA"; } }
}

输出：

GeneralWidgetService ID: 09f61af7-c70d-45fe-834a-6cc94e1e3c40
GeneralWidgetService ID: 09f61af7-c70d-45fe-834a-6cc94e1e3c40
WidgetController ID: 2c2bf05f-d251-41be-b9e0-224f02839ead
WidgetController ID: 2c2bf05f-d251-41be-b9e0-224f02839ead
GeneralWidgetService ID: 09f61af7-c70d-45fe-834a-6cc94e1e3c40
WidgetController ID: 519a2930-5b71-4cbb-b84e-a1d712ec5398

使用 Ninject，您如何根据绑定指定不同的生命周期？

With Ninject, how do you specify different lifetimes depending on the binding?

asp.net-mvc

ninject

httpmodule

lifetime