向Unity注册通用处理程序接口

Question

I've looked at multiple threads regarding registering generic interfaces in Unity, unfortunately I've not managed to get any of them to actually work. This is the interface that is defined.

public interface IHandler<in TCommand>{}

Example class:

public class MyTestHandler : IHandler<TestCommand>
{}

I'm then trying to resolve them in a factory:

    public IHandler<TCommand> Create<TCommand>()
    {
        return _container.Resolve<IHandler<TCommand>>();
    }

I've attempted to register my Handler as follows:

container.RegisterTypes(AllClasses.FromLoadedAssemblies().Where(type => typeof(IHandler<>).IsAssignableFrom(type)), WithMappings.FromAllInterfaces, WithName.TypeName, WithLifetime.Transient);

Unfortunately unless I explicitly register a concrete handler I can't seem to get it to work. Any suggestions would be great.

Thanks in advance.

Answer 1

The problem's the Where condition: IHandler<> is not assignable from MyTestHandler and therfore you get no registrations.

This works fine for me, that is, instance receives a MyTestHandler and instance2 receives a MyTestHandler2 :

internal class Program
{
    static void Main( string[] args )
    {
        var container = new UnityContainer();

        container.RegisterTypes( AllClasses.FromLoadedAssemblies().Where( type => type.Name.Contains("Handler") ), WithMappings.FromAllInterfaces, WithName.Default, WithLifetime.Transient );
        var instance = container.Resolve<IHandler<TestCommand>>();
        var instance2 = container.Resolve<IHandler<TestCommand2>>();
    }
}

public interface IHandler<TCommand>
{
}

public class MyTestHandler : IHandler<TestCommand>
{
}

public class TestCommand
{
}
public class MyTestHandler2 : IHandler<TestCommand2>
{
}

public class TestCommand2
{
}