Question

我有一个基于MassTransit的Windows服务上托管的应用程序。它针对.net Framework 4.6.2。现在，我将其移植到asp.net core 2.0。在.net框架上，我使用autofac的容器从指定的程序集中加载使用者。现在我要使用默认的asp.net核心的DI。有我的启动代码：

public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();

            services.RegisterAllTypes<IConsumer>(new Assembly[] { Assembly.Load("consumersLib") });

            var busControl = Bus.Factory.CreateUsingRabbitMq(cfg =>
            {
                var host = cfg.Host(new Uri("rabbithost"), h =>{...});

                cfg.ReceiveEndpoint("queue", ec =>
                {
                    ec.LoadFrom(services.BuildServiceProvider());
                });

            });
        }

并注册：

public static void RegisterAllTypes<T>(this IServiceCollection services, Assembly[] assemblies,
        ServiceLifetime lifetime = ServiceLifetime.Transient)
        {
            var typesFromAssemblies = assemblies.SelectMany(a => a.DefinedTypes.Where(x => x.GetInterfaces().Contains(typeof(T))));
            foreach (var type in typesFromAssemblies)
                services.Add(new ServiceDescriptor(typeof(T), type, lifetime));
        }

ec.LoadFrom（services.BuildServiceProvider（））引发异常：“对象引用未设置为对象的实例。”即使services.BuildServiceProvider（）已初始化并包含一些使用者。我看着masstransit的来源：

public static void LoadFrom(this IReceiveEndpointConfigurator configurator, IServiceProvider serviceProvider)
        {
            var consumerCache = serviceProvider.GetService<IConsumerCacheService>();

            var consumers = consumerCache.GetConfigurators();

            foreach (var consumer in consumers)
                consumer.Configure(configurator, serviceProvider);

            var sagaCache = serviceProvider.GetService<ISagaCacheService>();

            IEnumerable<ICachedConfigurator> sagas = sagaCache.GetConfigurators();

            foreach (var saga in sagas)
                saga.Configure(configurator, serviceProvider);
        }

，然后我发现一行serviceProvider.GetService（）返回null。有人知道如何解决吗？

Answer 1

有一个集成库，可将MassTransit与MS DI一起使用。

https://www.nuget.org/packages/MassTransit.Extensions.DependencyInjection/

也有记录：

http://masstransit-project.com/MassTransit/usage/containers/msdi.html

与asp.net core 2.0的masstransit DI集成

1 个答案: