C# ASP.Net 与 Autofac 集成时面临的核心问题

Question

我有一个控制器 DailyExpenseController，我正在将 IQueryExecutor class 注入控制器。

DailyExpenseController

using HomeBudgetTrackingSystem.CrossCutting;
using HomeBudgetTrackingSystem.DTO;
using HomeBudgetTrackingSystem.Models;
using HomeBudgetTrackingSystem.Query;
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;

namespace HomeBudgetTrackingSystem.Controllers
{
    [Produces("application/json")]
    [Route("api/DailyExpense/{Id}")]
    public class DailyExpenseController : Controller
    {
        private readonly IQueryExecutor queryExecutor;

        public DailyExpenseController(IQueryExecutor queryExecutor)
        {
            this.queryExecutor = queryExecutor;
        }

        [HttpPost]
        [Route("Create")]
        public async Task<IActionResult> CreateExpense(long Id, [FromBody] Expenditure expenditure)
        {
            var findEntity = new FindEntityQuery<Expense>(Id);
            var find = queryExecutor.Execute(findEntity);

            /*if (find == null)
                return NotFound();*/


            var createExpenses = new CreateExpenditure(expenditure);
            var expenses = queryExecutor.Execute(createExpenses);
            return Ok(expenses);
        }

        /*If I write this method, it will result in 500 Error, because this method has id which is confusing 
         with the variable Id declared with Controller*/
        /*[HttpGet("{id}")]
        public string Get(int id)
        {
            return "value";
        }*/

        [HttpGet("{id2}")]
        public string Get(long id)
        {
            return "value";
        }

        [HttpPost]
        public void Post([FromBody]string value)
        {
        }

    }
}

以下是我的 Autofac 配置详细信息

Startup.cs

using Autofac;
using Autofac.Extensions.DependencyInjection;
using HomeBudgetTrackingSystem.Repository;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using System;

namespace HomeBudgetTrackingSystem
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        //public void ConfigureServices(IServiceCollection services)
        public IServiceProvider ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            /*services.AddDbContext<BudgetContext>(options =>
             options.UseSqlServer(Configuration.GetConnectionString("BudgetConnection")
        )); */

            var builder = new ContainerBuilder();
            builder.Populate(services);
            builder.RegisterModule(new RepositoryHandlerModule());
            //builder.RegisterType<QueryExecutor>().As<IQueryExecutor>();
            ApplicationContainer = builder.Build();
            return new AutofacServiceProvider(ApplicationContainer);
        }

        public IContainer ApplicationContainer { get; private set; }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, IApplicationLifetime appLifetime)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseMvc();
            appLifetime.ApplicationStopped.Register(() => ApplicationContainer.Dispose());
        }
    }
}

下面是我的模型构建器class，我在其中注册了依赖关系

RepositoryHandlerModule.cs

using Autofac;
using HomeBudgetTrackingSystem.CrossCutting;

namespace HomeBudgetTrackingSystem.Repository
{
    public class RepositoryHandlerModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            builder.RegisterType<QueryExecutor>().As<IQueryExecutor>().InstancePerRequest();
        }
    }
}

我没有对 Program.cs

进行任何更改

Program.cs

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;

namespace HomeBudgetTrackingSystem
{
    public class Program
    {
        public static void Main(string[] args)
        {
            BuildWebHost(args).Run();
        }

        public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .Build();
    }
}

以下是我收到的异常详细信息

Autofac.Core.DependencyResolutionException: Unable to resolve the type 'HomeBudgetTrackingSystem.CrossCutting.QueryExecutor' because the lifetime scope it belongs in can't be located. The following services are exposed by this registration: - HomeBudgetTrackingSystem.CrossCutting.IQueryExecutor

Details ---> No scope with a tag matching 'AutofacWebRequest' is visible from the scope in which the instance was requested.

If you see this during execution of a web application, it generally indicates that a component registered as per-HTTP request is being requested by a SingleInstance() component (or a similar scenario). Under the web integration always request dependencies from the dependency resolver or the request lifetime scope, never from the container itself. (See inner exception for details.) ---> Autofac.Core.DependencyResolutionException: No scope with a tag matching 'AutofacWebRequest' is visible from the scope in which the instance was requested.

If you see this during execution of a web application, it generally indicates that a component registered as per-HTTP request is being requested by a SingleInstance() component (or a similar scenario). Under the web integration always request dependencies from the dependency resolver or the request lifetime scope, never from the container itself. at Autofac.Core.Lifetime.MatchingScopeLifetime.FindScope(ISharingLifetimeScope mostNestedVisibleScope) at Autofac.Core.Resolving.InstanceLookup..ctor(IComponentRegistration registration, IResolveOperation context, ISharingLifetimeScope mostNestedVisibleScope, IEnumerable1 parameters) --- End of inner exception stack trace --- at Autofac.Core.Resolving.InstanceLookup..ctor(IComponentRegistration registration, IResolveOperation context, ISharingLifetimeScope mostNestedVisibleScope, IEnumerable1 parameters) at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable1 parameters) at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable1 parameters) at Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable1 parameters, Object& instance) at Autofac.ResolutionExtensions.ResolveOptionalService(IComponentContext context, Service service, IEnumerable1 parameters) at Microsoft.Extensions.Internal.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired) at lambda_method(Closure , IServiceProvider , Object[] ) at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.b__0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.g__CreateController|0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.d__14.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__22.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__17.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__15.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Builder.RouterMiddleware.d__4.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.d__7.MoveNext()

我已经提到了关于这些的多个链接。突出的是

http://autofac.readthedocs.io/en/latest/faq/per-request-scope.html http://autofac.readthedocs.io/en/latest/integration/aspnetcore.html （我更喜欢没有容器的配置） http://www.codedigest.com/posts/49/using-autofac-instead-of-inbuilt-di-container-with-in-aspnet-core-mvc（这是我提到的）

谁能帮我解决这些问题？

Answer 1

我找到了问题的解决方案。

http://autofaccn.readthedocs.io/en/latest/integration/aspnetcore.html

这里在标题下'Differences From ASP.NET Classic'，列出了一个关键点使用 InstancePerLifetimeScope 而不是 InstancePerRequest。

我也对 RepositoryHandlerModule.cs 进行了更改，例如添加 BudgetContext.cs 如下

public class RepositoryHandlerModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            base.Load(builder);
            builder.RegisterType<QueryExecutor>().As<IQueryExecutor>().InstancePerLifetimeScope();
            builder.RegisterType<BudgetContext>().InstancePerLifetimeScope();
        }
    }

C# ASP.Net 与 Autofac 集成时面临的核心问题

C# ASP.Net Core facing issues when integrating with Autofac

c#

dependency-injection

autofac

asp.net-core-1.1