C# 如何获得在Unity中被注入的对象的类型？

我有一个类型在其构造函数中接收另一个类型，通常是创建它的对象的类型，例如：

public class Logger {
    public Logger(Type parent) { ... }
}

我想指示Unity解析

Logger

将需要它的对象类型作为参数传递给它的构造函数。比如：

// ... would be some directive to tell Unity to use the type that
/// depends on Logger
container.RegisterType<Logger>(new InjectionConstructor(...));

它将返回：

var logger = new Logger(typeof(MyService));
return new MyService(logger);

---

可能吗？还有其他方法吗？

实际上，您可以这样做：

internal class Program
{
    static void Main( string[] args )
    {
        var container = new UnityContainer();
        container.RegisterType<IInterface, Implementation>( new MyInjectionConstructor() );

        // this instance will get a logger constructed with loggedType == typeof( Implementation )
        var instance = container.Resolve<IInterface>();
    }
}

internal class MyInjectionConstructor : InjectionMember
{
    public override void AddPolicies( Type serviceType, Type implementationType, string name, IPolicyList policies )
    {
        policies.Set<IConstructorSelectorPolicy>( new MyConstructorSelectorPolicy(), new NamedTypeBuildKey( implementationType, name ) );
    }
}

internal class MyConstructorSelectorPolicy : DefaultUnityConstructorSelectorPolicy
{
    protected override IDependencyResolverPolicy CreateResolver( ParameterInfo parameter )
    {
        if( parameter.ParameterType == typeof( ILogger ) )
        {
            return new LiteralValueDependencyResolverPolicy( new Logger( parameter.Member.DeclaringType ) );
        }
        return base.CreateResolver( parameter );
    }
}

internal interface ILogger
{
}

internal class Logger : ILogger
{
    public Logger( Type loggedType )
    {
    }
}

internal interface IInterface
{
}

internal class Implementation : IInterface
{
    public Implementation( ILogger logger )
    {
    }
}

内部类程序
{
静态void Main（字符串[]参数）
{
var container=new UnityContainer（）；
RegisterType（新的MyInjectionConstructor（））；
//此实例将获得一个使用loggedType==typeof（实现）构造的记录器
var instance=container.Resolve（）；
}
}
内部类MyInjectionConstructor:InjectionMember
{
public override void AddPolicies（类型serviceType、类型implementationType、字符串名称、IPolicyList策略）
{
Set（new MyConstructorSelectorPolicy（），new NamedTypeBuildKey（implementationType，name））；
}
}
内部类MyConstructorSelectorPolicy:DefaultUnityConstructorSelectorPolicy
{
受保护的重写IDependencySolverPolicy CreateSolver（ParameterInfo参数）
{
if（parameter.ParameterType==typeof（ILogger））
{
返回新的LiteralValueDependencySolverPolicy（新记录器（parameter.Member.DeclaringType））；
}
返回base.CreateResolver（参数）；
}
}
内部接口ILogger
{
}
内部类记录器：ILogger
{
公共记录器（类型loggedType）
{
}
}
内部接口接口
{
}
内部类实现：IInterface
{
公共实现（ILogger记录器）
{
}
}

这只是概念验证代码，可能需要在生产使用前进行一些改进

internal class Program
{
    static void Main( string[] args )
    {
        var container = new UnityContainer();
        container.RegisterType<IInterface, Implementation>( new MyInjectionConstructor() );

        // this instance will get a logger constructed with loggedType == typeof( Implementation )
        var instance = container.Resolve<IInterface>();
    }
}

internal class MyInjectionConstructor : InjectionMember
{
    public override void AddPolicies( Type serviceType, Type implementationType, string name, IPolicyList policies )
    {
        policies.Set<IConstructorSelectorPolicy>( new MyConstructorSelectorPolicy(), new NamedTypeBuildKey( implementationType, name ) );
    }
}

internal class MyConstructorSelectorPolicy : DefaultUnityConstructorSelectorPolicy
{
    protected override IDependencyResolverPolicy CreateResolver( ParameterInfo parameter )
    {
        if( parameter.ParameterType == typeof( ILogger ) )
        {
            return new LiteralValueDependencyResolverPolicy( new Logger( parameter.Member.DeclaringType ) );
        }
        return base.CreateResolver( parameter );
    }
}

internal interface ILogger
{
}

internal class Logger : ILogger
{
    public Logger( Type loggedType )
    {
    }
}

internal interface IInterface
{
}

internal class Implementation : IInterface
{
    public Implementation( ILogger logger )
    {
    }
}