.NET 8 中工厂类是如何注册的？

Question

有人可以告诉我如何在 .NET 8 中注册以下工厂吗？:

public class DefaultViewFactory : IViewFactory
{
    private readonly IServiceProvider _serviceProvider;

    public DefaultViewFactory(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public TView CreateView<TView>()
    {
        var service = _serviceProvider.GetService<IViewBuilder<TView>>();

        return service != null ? service.Build() : Activator.CreateInstance<TView>();
    }

    public TView CreateView<TInput, TView>(TInput input)
    {
        var service = _serviceProvider.GetService<IViewBuilder<TInput, TView>>();

        if (service != null)
        {
            return service.Build(input);
        }

        return (TView)Activator.CreateInstance(typeof(TView), input)!;
    }
}

我已将以下代码添加到 Program.cs 文件中：

serviceCollection.AddTransient<IViewFactory, DefaultViewFactory>();

以前使用 StructureMap，会使用以下内容：

configurationExpression.Scan(assemblyScanner =>
{
    assemblyScanner.TheCallingAssembly();
    assemblyScanner.ConnectImplementationsToTypesClosing(typeof(IViewBuilder<>));
    assemblyScanner.ConnectImplementationsToTypesClosing(typeof(IViewBuilder<,>));
})

有人可以建议替代实施吗？

我添加了IViewBuilder以供参考：

public interface IViewBuilder<out TView>
{
    TView Build();
}

public interface IViewBuilder<in TInput, out TView>
{
    TView Build(TInput input);
}

Answer 1

.NET（Core）内置DI不支持程序集扫描和匹配封闭泛型类型。

如果您有一个开放通用实现，那么您可以将其注册为开放通用：

services.AddTransient(typeof(IViewBuilder<>), typeof(SomeGenericViewBuilder<>));
services.AddTransient(typeof(IViewBuilder<,>), typeof(SomeGenericViewBuilder<,>));

如果您有不同的类型实现接口，那么您可以：

• 手动注册它们：

  services.AddTransient(typeof(IViewBuilder<SomeView>), typeof(SomeViewBuilder));
  // ...
  

• 自己编写汇编扫描代码（使用反射API）

• 使用一些库，如

  Scrutor

  （未测试）：

  var collection = new ServiceCollection();
  
  collection.Scan(scan => scan
     // We start out with all types in the assembly
      .FromAssemblyOf<ViewBuildersAssemblyTypeLandmark>()
        // Generic interfaces are also supported too
        .AddClasses(classes => classes.AssignableTo(typeof(IViewBuilder<>)))
            .AsImplementedInterfaces()
        // And you scan generics with multiple type parameters 
        .AddClasses(classes => classes.AssignableTo(typeof(IViewBuilder<,>)))
            .AsImplementedInterfaces());
  

• 研究用支持所需功能的容器替换默认服务容器