Autofac.Extras.AttributeMetadata

Attribute metadata support for Autofac IoC

Please file issues and pull requests for this package in this repository rather than in the Autofac core repo.

• Documentation
• NuGet
• Contributing
• Open in Visual Studio Code

Quick Start

First, create a metadata attribute - any System.Attribute that has MEF's [MetadataAttribute] applied. Every publicly readable property becomes one metadata name/value pair, so the attribute below provides Age metadata:

[MetadataAttribute]
public class AgeMetadataAttribute : Attribute
{
  public int Age { get; private set; }

  public AgeMetadataAttribute(int age)
  {
    Age = age;
  }
}

Apply it to the component implementation rather than to the service interface:

public interface IArtwork
{
  void Display();
}

[AgeMetadata(100)]
public class CenturyArtwork : IArtwork
{
  public void Display() { ... }
}

Then register the AttributedMetadataModule so the container reads those attributes, and consume the metadata as you would any other:

var builder = new ContainerBuilder();
builder.RegisterModule<AttributedMetadataModule>();
builder.RegisterType<CenturyArtwork>().As<IArtwork>();
var container = builder.Build();

var artwork = container.Resolve<IEnumerable<Meta<IArtwork>>>()
                       .First(a => a.Metadata["Age"].Equals(100));
artwork.Value.Display();

You can read more details in the documentation.

Get Help

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