Use Autofac IoC Container in ASP.NET or ASP.NET Core

Summary

This context provides a tutorial on how to use the Autofac IoC container in ASP.NET and ASP.NET Core applications.

Abstract

The text begins by introducing Autofac, an IoC container for .NET that helps manage dependencies between classes in applications, making them easier to change as they grow in size and complexity. It then discusses the limitations of the built-in dependency injection framework in .NET Core and highlights the advantages of using Autofac, such as resolving a service with associated metadata, named/keyed services, and multi-tenant support. The tutorial covers the steps to configure Autofac in an ASP.NET Core application, including installing the necessary NuGet packages, configuring the host builder, and adding a ConfigureContainer method to the Startup class. It also explains the concept of Autofac modules and their use cases. The text concludes by summarizing the benefits of using Autofac over the built-in IoC container in .NET Core for large-scale projects.

Opinions

Autofac is a popular and powerful IoC container for ASP.NET and works flawlessly with .NET Core.
The built-in dependency injection framework in .NET Core may not offer enough functionality for growing systems, and Autofac provides additional features like resolving a service with associated metadata, named/keyed services, and multi-tenant support.
Autofac modules provide a modular approach to configuring the container, allowing for new or customized mechanisms and packaging optional application features as 'plug-ins'.
Using Autofac may require extra coding in some cases, but its rich functionality brings more benefits for large-scale projects.
The tutorial provides a step-by-step guide to configuring Autofac in an ASP.NET Core application, including code examples and a sample source code on GitHub.

TL;DR

Autofac is an IoC container for .NET. It manages the dependencies between classes so that applications stay easy to change as they grow in size and complexity. Autofac is the most popular DI/IoC container for ASP.NET and it works with .NET Core flawlessly.

.NET Core gives you a built-in dependency injection framework. Though the default DI may offer enough functionality, there is a certain limitations like resolving a service with some associated Metadata, Named/Keyed services, Aggregate Services, Multi-tenant support, lazy instantiation, and much more. As the system grows you might need such features, and Autofac gives you all these features.

Configure Autofac in ASP.NET Core application

1. NuGet: To use Autofac, you need to install below NuGet packages.

PM> Install-Package Autofac
PM> Install-Package Autofac.Extensions.DependencyInjection

2. Configuration: Configure Host builder, typically this is your Program.cs and insert .UseServiceProviderFactory(new AutofacServiceProviderFactory()). The core of the integration is the AutofacServiceProviderFactory. It enables Autofac as DI container in your ASP.NET Core Application.

3. Add a ConfigureContainer method to Startup class. ConfigureServices method is called by .NET Core at application startup time to register additional services. The ConfigureContainer method registers the components in the container using the container's native APIs.

Autofac Module

4. Usage: You are done with Autofac configuration. Now for injecting the dependency, it is same code that we use using with default DI.

Autofac Modules Use Cases

A module is a small class that can be used to bundle up a set of related components behind a ‘facade’ to simplify configuration and deployment. The module exposes a deliberate, restricted set of configuration parameters that can vary independently of the components used to implement the module.

Modular approach. New or customized mechanisms for configuring the container.

Configure related services that provide a subsystem.

Package optional application features as ‘plug-ins’.

Provide pre-built packages for integration with a system.

Sample source code on GitHub.