无法使用 dotnet 核心和 autofac 将 ServiceCollection 类型的对象转换为类型 'Autofac.ContainerBuilder'

Question

我正在尝试在我的 dotnet core 3.1 项目中使用 autofac，但是在 startup.cs 文件中写入 ConfigureContainer 后我无法运行项目.

    public void ConfigureContainer(ContainerBuilder builder)
    {

        var databaseConnectionString = Configuration.GetConnectionString("Database");

        builder.RegisterModule(new MediatorModule());
        builder.RegisterModule(new ApplicationModule(databaseConnectionString));
    }

我得到的错误是：

System.InvalidCastException: Unable to cast object of type
'Microsoft.Extensions.DependencyInjection.ServiceCollection' to type 'Autofac.ContainerBuilder'. at Microsoft.Extensions.Hosting.Internal.ConfigureContainerAdapter`1.ConfigureContainer(HostBuilderContext hostContext, Object containerBuilder) at Microsoft.Extensions.Hosting.HostBuilder.CreateServiceProvider() at Microsoft.Extensions.Hosting.HostBuilder.Build() at Program.Main(String[] args) in C:\src\Program.cs:line 39

Answer 1

配置主机时，您应该调用 UseServiceProviderFactory(new AutofacServiceProviderFactory())

public static void Main(string[] args)
{
    // ASP.NET Core 3.0+:
    // The UseServiceProviderFactory call attaches the
    // Autofac provider to the generic hosting mechanism.
    var host = Host.CreateDefaultBuilder(args)
                   .UseServiceProviderFactory(new AutofacServiceProviderFactory())
                   .ConfigureWebHostDefaults(webHostBuilder => {
                       webHostBuilder
                        .UseContentRoot(Directory.GetCurrentDirectory())
                        .UseIISIntegration()
                        .UseStartup<Startup>();
                   })
                   .Build();

    host.Run();
}

如果没有这个，.net core 将创建一个 ServiceCollection 而不是 ContainerBuilder 并且将抛出一个 InvalidCastException。

无法使用 dotnet 核心和 autofac 将 ServiceCollection 类型的对象转换为类型 'Autofac.ContainerBuilder'

Unable to cast object of type ServiceCollection to type 'Autofac.ContainerBuilder' using dotnet core and autofac

c#

autofac

.net-core