Onion 架构中的 Autofac WebForms

Question

我正在关注洋葱架构，其引导程序部分是使用 Autofac 构建的。

架构如下：

1. 核心
2. DependencyInjection（Autofac 在这里）
3. 服务
4. 演示文稿 (MVC 5)
5. 测试

我需要一些 WebForm.aspx 页面来显示我的报告。所以我按照给出的链接将 WebForms 与 Autofac 集成的说明进行操作：http://docs.autofac.org/en/latest/integration/webforms.html

这是来自 DependencyInjection 的代码：

[assembly: WebActivatorEx.PreApplicationStartMethod(typeof(IocConfig), "RegisterDependencies")]
namespace DependencyInjection.App_Start
{
    public class IocConfig : IContainerProviderAccessor
    {
         // Provider that holds the application container.
        static IContainerProvider _containerProvider;

        // Instance property that will be used by Autofac HttpModules
        // to resolve and inject dependencies.
        public IContainerProvider ContainerProvider
        {
            get { return _containerProvider; }
        }

        public static void RegisterDependencies()
        {
            // Build up your application container and register your dependencies.
            var builder = new ContainerBuilder();

            // Register your MVC controllers. (MvcApplication is the name of
            // the class in Global.asax.)
            builder.RegisterControllers(typeof(MvcApplication).Assembly);

            // OPTIONAL: Register model binders that require DI.
            builder.RegisterModelBinders(typeof(MvcApplication).Assembly);
            builder.RegisterModelBinderProvider();

            // OPTIONAL: Register web abstractions like HttpContextBase.
            builder.RegisterModule<AutofacWebTypesModule>();

            // OPTIONAL: Enable property injection in view pages.
            builder.RegisterSource(new ViewRegistrationSource());



            // OPTIONAL: Enable property injection into action filters.
            builder.RegisterFilterProvider();

 builder.RegisterType<MyService().As<IMyService().InstancePerRequest();

            // Once you're done registering things, set the container
           // provider up with your registrations.
           _containerProvider = new ContainerProvider(container);
        }
    }
}

在 DependencyInjection 的 App.Config 中，我添加了：

<system.web>
    <httpModules>      
      <add name="ContainerDisposal" type="Autofac.Integration.Web.ContainerDisposalModule, Autofac.Integration.Web"/>
      <add name="PropertyInjection" type="Autofac.Integration.Web.Forms.PropertyInjectionModule, Autofac.Integration.Web"/>
    </httpModules>
  </system.web>
  <system.webServer>
    <modules>
      <add name="ContainerDisposal" type="Autofac.Integration.Web.ContainerDisposalModule, Autofac.Integration.Web" preCondition="managedHandler"/>
      <add name="PropertyInjection" type="Autofac.Integration.Web.Forms.PropertyInjectionModule, Autofac.Integration.Web" preCondition="managedHandler"/>
    </modules>    
  </system.webServer>

仍然无法正常工作。 MyService 仍然是null。当我将 App.Config 设置添加到我的 Presentation 的 Web.Config 中时，出现以下错误：

此模块需要 HttpApplication（全局应用程序 类）实现 IContainerProviderAccessor

Answer 1

Autofac ASP.net WebForm 集成要求HttpApplication 实现IContainerProviderAccessor。

如果你想在你的IocConfig 类中使用WebActivator。 Global.asax 类还是要实现IContainerProviderAccessor 接口让HttpModule 找到Autofac 容器。

你可以通过依赖IocConfig实现来实现这个接口

Global.asax.cs

public class Global : HttpApplication, IContainerProviderAccessor
{
  // Instance property that will be used by Autofac HttpModules
  // to resolve and inject dependencies.
  public IContainerProvider ContainerProvider
  {
    get { return IocConfig.ContainerProvider; }
  }
}

您的IocConfig 不需要实现IContainerProviderAccessor，但需要为IContainerProvider 提供一个公共静态属性

[assembly: WebActivatorEx.PreApplicationStartMethod(typeof(IocConfig), 
                                                   "RegisterDependencies")]

namespace DependencyInjection.App_Start
{
    public class IocConfig : IContainerProviderAccessor
    {
         // Provider that holds the application container.
        static IContainerProvider _containerProvider;

        // Instance property that will be used by Autofac HttpModules
        // to resolve and inject dependencies.
        public static IContainerProvider ContainerProvider
        {
            get { return _containerProvider; }
        }