在 netcore 中使用 autofac 的 registerType 异常

Question

This is not an issue, but a question. I have the following sample code:

class CommonArgs{
}

class TestArgs : CommonArgs{
}

abstract class AbstractHandler where T: CommonArgs, new (){
}

class TestHandler: AbstractHandler{
}

I use autofac to register the type:

builder.RegisterType (typeof (TestHandler)). Named ("testHandler", typeof (AbstractHandler<>)). InstancePerLifetimeScope ();

When I build.Build () , I get an exception:

System.ArgumentException: "The type 'TestHandler' is not assignable to service 'testHandler (AbstractHandler`1)'."

What is the correct type of registration? （use dotnet core Autofac 4.8.1）

Answer 1

You were almost there, just use the RegisterType overload and a Named with some string key and a typeof(AbstractHandler<CommonArgs>))

Here is a link to my github with a small unit-test to issue your question.

Code:

ContainerBuilder builder = new ContainerBuilder();            
builder.RegisterType<TestHandler>().Named("myTestHandler", typeof(AbstractHandler<CommonArgs>));

IContainer container = builder.Build();

var testHandler = container.ResolveNamed("myTestHandler", typeof(AbstractHandler<CommonArgs>));