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About

System.Composition.Convention is part of the Managed Extensibility Framework (MEF) 2.0, a composition library for .NET that enables dependency injection through attributes or conventions.

This package simplifies the process of applying consistent patterns for part exports, imports, and metadata by using convention-based configurations. It is useful for scenarios where you want to avoid repetitive attribute-based decoration and instead define conventions for registering types in your composition container.

Key Features

Configure exports, imports, and metadata for parts using conventions rather than attributes.
Allows defining conventions through a fluent API, making configuration more flexible and readable.

How to Use

Configure parts for composition without using attributes.

using System.Composition.Convention;
using System.Composition.Hosting;

var conventions = new ConventionBuilder();

// Apply conventions: any class that implements ILogger will be exported as ILogger
conventions
    .ForTypesDerivedFrom<ILogger>()
    .Export<ILogger>();

var configuration = new ContainerConfiguration()
    .WithPart<FileLogger>(conventions)
    .WithPart<ConsoleLogger>(conventions);

using CompositionHost container = configuration.CreateContainer();
    
var loggers = container.GetExports<ILogger>();

foreach (var logger in loggers)
{
    logger.Log("Hello, World!");
}
// FileLogger: Hello, World!
// ConsoleLogger: Hello, World!

public interface ILogger
{
    void Log(string message);
}

public class FileLogger : ILogger
{
    public void Log(string message) => Console.WriteLine($"FileLogger: {message}");
}

public class ConsoleLogger : ILogger
{
    public void Log(string message) => Console.WriteLine($"ConsoleLogger: {message}");
}

Main Types

The main types provided by this library are:

System.Composition.Convention.ConventionBuilder
System.Composition.Convention.PartConventionBuilder
System.Composition.Convention.ParameterImportConventionBuilder

Additional Documentation

Feedback & Contributing

System.Composition.Convention is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.

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