How to Split services registrations in .Net core DI using Extension Methods?
Tags: csharp
Published: 2023-01-10 19:50:06

---
title: How to Split services registrations in .Net core DI using Extension Methods?
published: true
date: 2022-12-24 19:07:25 UTC
tags: csharp
canonical_url: https://mbarkt3sto.hashnode.dev/how-to-split-services-registrations-in-net-core-di-using-extension-methods
---

In .NET Core, the built-in dependency injection (DI) container makes it easy to register and resolve dependencies in your applications. You can use the container to manage the lifetime of your dependencies and inject them into your classes as needed.

## **Splitting Services Registrations in .NET Core DI**

As your application grows, you may find that your DI container becomes cluttered with a large number of service registrations. To help manage this complexity, you can use extension methods to split your service registrations into smaller, more manageable chunks.

## **Creating an Extension Method**

To create an extension method, you need to create a static class with one or more static methods that have the `this` keyword in their parameter list. For example, consider the following extension method for registering a collection of services:

```
public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddMyServices(this IServiceCollection services)
    {
        services.AddTransient<IMyService, MyService>();
        services.AddTransient<IAnotherService, AnotherService>();
        // Add additional service registrations here...

        return services;
    }
}

```

This extension method can be called on an `IServiceCollection` instance to add a collection of services to the DI container.

## **Using the Extension Method**

To use the extension method, you can call it on the `IServiceCollection` instance in your application's `Startup` class. For example:

```
public void ConfigureServices(IServiceCollection services)
{
    // Add other service registrations here...
    services.AddMyServices();
}

```

By using extension methods to split your service registrations into smaller chunks, you can make your DI container more organized and easier to maintain.

## **Example: Splitting Services by Feature**

One common way to split service registrations is by feature or module. For example, consider a simple application with two features: `FeatureA` and `FeatureB`. You could create separate extension methods for each feature, like this:

```
public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddFeatureAServices(this IServiceCollection services)
    {
        services.AddTransient<IFeatureAService, FeatureAService>();
        // Add additional Feature A service registrations here...

        return services;
    }

    public static IServiceCollection AddFeatureBServices(this IServiceCollection services)
    {
        services.AddTransient<IFeatureBService, FeatureBService>();
        // Add additional Feature B service registrations here...

        return services;
    }
}

```

Then, in the `ConfigureServices` method of the `Startup` class, you can call the appropriate extension method for each feature:

```
public void ConfigureServices(IServiceCollection services)
{
    // Add other service registrations here...
    services.AddFeatureAServices();
    services.AddFeatureBServices();
}

```

## **Example: Splitting Services by Infrastructure**

Another common way to split service registrations is by infrastructure or cross-cutting concern. For example, you might have a set of services that are related to logging, another set related to caching, and another set related to security. You could create separate extension methods for each infrastructure layer, like this:

```
public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddLoggingServices(this IServiceCollection services)
    {
        services.AddSingleton<ILoggerFactory, LoggerFactory>();
        services.AddSingleton(typeof(ILogger<>), typeof(Logger<>));
        // Add additional logging service registrations here...

        return services;
    }

    public static IServiceCollection AddCachingServices(this IServiceCollection services)
    {
        services.AddSingleton<ICacheManager, CacheManager>();
        // Add additional caching service registrations here...

        return services;
    }

    public static IServiceCollection AddSecurityServices(this IServiceCollection services)
    {
        services.AddTransient<ITokenService, TokenService>();
        // Add additional security service registrations here...

        return services;
    }
}

```

Then, in the `ConfigureServices` method of the `Startup` class, you can call the appropriate extension method for each infrastructure layer:

```
public void ConfigureServices(IServiceCollection services)
{
    // Add other service registrations here...
    services.AddLoggingServices();
    services.AddCachingServices();
    services.AddSecurityServices();
}

```

This approach allows you to easily manage and maintain the different infrastructure layers of your application separately.

Splitting service registrations in .NET Core DI using extension methods can help improve the maintainability and organization of your application's DI container. By dividing your registrations into smaller, more manageable chunks, you can more easily manage the dependencies of your application and make it easier to change or replace components at runtime.