如何使用条件装饰器通过委托工厂解析服务？

Question

我有一个类hirerachy，看起来像这样：

public class Foo : IFoo 
{ 
    private readonly IBar _bar; 

    public Foo(IBar bar) 
     => _bar = bar; 
} 

public class Bar : IBar 
{ 
    private readonly Func<IFoo> _fooFunc; 
    private readonly IBaz _baz; 

    public Bar(Func<IFoo> fooFunc, IBaz baz) 
    { 
     _fooFunc = fooFunc; 
     _baz = baz; 
    } 
} 

public class Baz : IBaz 
{ 
} 

public class BazDecorator : IBaz 
{ 
    private readonly IBaz _decoratee; 

    public BarDecorator(IBaz decoratee) 
     => _decoratee = decoratee; 
} 

注意Bar解决了IFoo时需要Func<IFoo>，而不是直接IFoo由于循环依赖的。

我目前的注册看起来喜欢这样的：

public class MyModule : Module 
{ 
    protected override void Load(ContainerBuilder builder) 
    { 
     builder.RegisterType<Foo>().As<IFoo>(); 

     builder.RegisterType<Bar>().As<IBar>(); 

     // Func<IFoo> is automatically resolved in AutoFac 

     builder.RegisterType<Baz>().Named<IBaz>("baz"); 

     builder.RegisterDecorator<IBaz>((c, inner) => 
      new BazDecorator(inner), 
      fromKey: "baz"); 
    } 
} 

我想只有有条件注册BazDecorator通过Foo但不Func<IFoo>像解决时：

Foo------Bar-----BazDecorator----Baz 
      \ 
      \ 
      \____Foo----Bar----Baz 

我如何注册我的服务在AutoFac中？

Answer 1

您需要手动注册Func<IFoo>，明确地传递正确的参数到Foo和Bar组件

builder.Register<Func<IFoo>>(c => 
    { 
     var ctx = c.Resolve<IComponentContext>(); 
     return() => new Foo(new Bar(() => ctx.Resolve<IFoo>(), ctx.ResolveNamed<IBaz>("baz"))); 
    }); 

如果你不想“新” Foo和Bar内Register功能，它也可以通过解决它们从容器中实现，但代码看起来相当讨厌：

builder.Register<Func<IFoo>>(c => 
    { 
     var ctx = c.Resolve<IComponentContext>(); 
     return() => ctx.Resolve<IFoo>(
      new ResolvedParameter(
       (p, cx) => p.Name == "bar", 
       (p, cx) => cx.Resolve<IBar>(new ResolvedParameter(
        (p1, c1) => p1.Name == "baz", 
        (p1, c1) => c1.ResolveNamed<IBaz>("baz"))))); 
    });