Autofac - How to get class name while creating instance

Question

I have question about Autofac : How can I get name of class which request instance from container?

Is it possible to get name of the class "Autofac_Test" passed into constructor by autofac when object is created?

My code:

using System;
using System.Diagnostics;
using System.Reflection;
using Autofac;
using Xunit;

public class BootStrap
{
    public IContainer Configure()
    {
        var builder = new ContainerBuilder();
        builder.Register(b => new MyLogger(MethodBase.GetCurrentMethod().ReflectedType)).As<ILog>();
        return builder.Build();
    }
}
public class Autofac_Test
{
    private IContainer _containter;
    public Autofac_Test()
    {
        _containter = new BootStrap().Configure();
    }
    [Fact]
    public void Should_create_class_with_Name_BlaBla()
    {
        var logger = _containter.Resolve<ILog>();
        Assert.True(logger.Name == "Autofac_Test");
    }
}
public class MyLogger : ILog
{
    public string Name { get; private set; }
    public MyLogger(Type name)
    {
        Name = name.FullName;
    }
    public void Info(string message)
    {
        Debug.WriteLine(string.Format("{0} {1}", Name, message));
    }
}

public interface ILog
{
    void Info(string message);
    string Name { get; }
}

Answer 1

For your specific case it will be quite difficult to obtain this information. But as I understand the question, MyLogger need to know the type name where it will be injected and the code sample may not be relevant.

In this case you can use a module and the Preparing event :

public class LoggingModule : Autofac.Module
{
    protected override void AttachToComponentRegistration(
        IComponentRegistry componentRegistry, IComponentRegistration registration)
    {
        registration.Preparing += (sender, e) =>
        {
            Type limitType = e.Component.Activator.LimitType;
            e.Parameters = e.Parameters.Union(new[] {
                new ResolvedParameter((pi, c) => pi.ParameterType == typeof(ILogger), 
                                      (pi, c) => c.Resolve<ILogger>(new NamedParameter("name", limitType.Name))),
            });
        };
    }
}

Then you will have to register your module like this :

ContainerBuilder builder = new ContainerBuilder();
builder.RegisterModule<LoggingModule>();
builder.RegisterType<MyLogger>().As<ILogger>();

Now each time a ILogger will be injected to a type it will have the correct name.

class Foo
{
    public Foo(ILogger logger)
    {
        this._loggerName = logger.Name;
    }

    private readonly String _loggerName; 

    public String LoggerName 
    {
        get 
        {
            return this._loggerName;
        }
    }
}

LoggerName will be Foo.

Your test can now look like this :

[Fact]
public void Should_create_class_with_Name_BlaBla()
{
    var foo = _containter.Resolve<Foo>();
    Assert.AreEquals("foo", foo.LoggerName, "invalid loggerName");
}