Resolve one of multiple registrations with DryIoc

问题

Given the small example below, is there a way to mark (attribute, name convention,... ) the MyInterface argument in MyService2, so that it will resolve correctly, or is the only way to pass in MyInterface[] ? I know that Castle Windsor can resolve it based on naming convention, but I haven't found something similar in DryIoc

public interface MyInterface { }

public class MyImplementationA : MyInterface { }

public class MyImplementationB : MyInterface { }

public class MyService1
{
    public MyService1(MyInterface[] implementations) {
        Console.WriteLine(implementations.GetType().Name);
    }
}

public class MyService2
{
    public MyService2(MyInterface implementationA) {
        Console.WriteLine(implementationA.GetType().Name);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var c = new Container();
        c.Register<MyInterface, MyImplementationA>(serviceKey: "implementationA");
        c.Register<MyInterface, MyImplementationB>(serviceKey: "implementationB");

        c.Register<MyService1>();
        c.Register<MyService2>();

        var a = c.Resolve<MyService1>();
        var b = c.Resolve<MyService2>();
    }
}

回答1:

There are number of ways:

First by using service keys as in your comment

Here the consumer selects dependency based on key.

c.Register<MyService2>(made: Made.Of(() => 
    new MyService2(Arg.Of<MyInterface>(ServiceKeys.ImplementationA))));

update: or in constructor agnostic way

c.Register<MyService2>(made:
    Parameters.Of.Type<MyInterface>(ServiceKeys.ImplementationA));

Dependency condition

Dependency selects the consumer based on condition:

c.Register<MyInterface, MyImplementationA>(setup: Setup.With(
    condition: request => request.Parent.ServiceType == typeof(MyService2)));

Dependency is reused in resolution scope of specific consumer

It won't be Transient anymore, but it may be OK depending on your setup.

c.Register<MyService2>(setup: Setup.With(openResolutionScope: true));
c.Register<MyInterface, MyImplementationA>(Reuse.InResolutionScopeOf<MyService2>());

回答2:

Your registration was ok

c.Register<MyInterface, MyImplementationA>(serviceKey: "implementationA");
c.Register<MyInterface, MyImplementationB>(serviceKey: "implementationB");

If you want to Resolve a concrete Instance for A or B, you can get it easier by this:

var a = c.Resolve<MyInterface>(serviceKey: "implementationA");
var b = c.Resolve<MyInterface>(serviceKey: "implementationB");

来源：https://stackoverflow.com/questions/34612600/resolve-one-of-multiple-registrations-with-dryioc

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