如何使用 .NET Core 注入通用接口

Question

我有下一个错误：

System.ArgumentException: '无法实例化实现类型

要注入的接口：

public interface iContext<T> { }

这个界面怎么用？

public class UsersRepository : iUsersRepository
{
    readonly iContext<UserEntities> db;
    public UsersRepository(iContext<UserEntities> db)
    {
        this.db = db;
    }
}

如何在启动时添加：

//services.AddScoped(typeof(iContext<>), typeof(UserEntities));
services.AddScoped(typeof(iContext<>));
//services.AddTransient<iContext<UserEntities>>();
//services.AddSingleton<iContext<UserEntities>, UserEntities>();

已编辑：

System.ArgumentException: Cannot instantiate implementation type 'Infrastructure._01_DataAccess.iContext`1[T]' for service type 'Infrastructure._01_DataAccess.iContext`1[T]'.
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.Populate()
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory..ctor(IEnumerable`1 descriptors)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine..ctor(IEnumerable`1 serviceDescriptors, IServiceProviderEngineCallback callback)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CompiledServiceProviderEngine..ctor(IEnumerable`1 serviceDescriptors, IServiceProviderEngineCallback callback)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable`1 serviceDescriptors, ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services, ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.DefaultServiceProviderFactory.CreateServiceProvider(IServiceCollection containerBuilder)
   at Microsoft.Extensions.Hosting.Internal.ServiceFactoryAdapter`1.CreateServiceProvider(Object containerBuilder)
   at Microsoft.Extensions.Hosting.HostBuilder.CreateServiceProvider()
   at Microsoft.Extensions.Hosting.HostBuilder.Build()
   at WebApi.Program.Main(String[] args) in C:\Users\Daviel.SPAIN-HOLIDAY\Source\Repos\dhmaker-user\WebApi\Program.cs:line 16

Answer 1

你需要注册一个实现iContext<T>的具体类，像这样：

services.AddScoped(typeof(iContext<>), typeof(Context<>));

其中Context<T> 是实现iContext<T> 的类。