Dependency Injection is a Curse to Developers in .NET? Or Is It?

5 min readSep 30, 2024

If you’ve spent any time working with .NET or .NET Core, you’ve likely encountered the concept of Dependency Injection (DI). For some developers, DI is a game-changing, must-have technique that keeps their code clean and maintainable. For others, it’s a curse that complicates code and causes more headaches than it solves.

Is Dependency Injection really a curse to .NET developers? Or is it one of those tools we just need to understand better?

Let’s dive deep into this controversy and explore the pros, cons, and how you can make DI work for you, not against you.

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What Exactly is Dependency Injection (DI)?

For those who are new to the idea, let’s clarify:

Dependency Injection is a technique where you pass (or inject) a service or dependency into a class, rather than having the class create or manage it on its own. In .NET, DI is heavily used, often through built-in IOC containers (Inversion of Control containers).

Consider this example:

public class OrderService
{
    private readonly IEmailService _emailService;

    public OrderService(IEmailService emailService)
    {
        _emailService = emailService;
    }

    public void ProcessOrder(Order order)
    {
        // Order processing logic
        _emailService.SendOrderConfirmation(order);
    }
}

Instead of OrderService creating an instance of EmailService, it receives it from outside, making OrderService independent of how the EmailService is created.

Sounds pretty neat, right?

The Praise: Why Developers Love DI in .NET

Let’s start by looking at why DI is such a praised technique in the development community.

1. Decoupling Your Code

Imagine you have an application with multiple services. Without DI, your classes are tightly coupled:

public class OrderService
{
    private readonly EmailService _emailService = new EmailService();
    // Tightly coupled, hard to test or extend
}

Tightly coupled code is difficult to test, maintain, and change. DI decouples these dependencies, making code easier to extend and unit test.

2. Easier Testing and Mocking

Want to test your OrderService class without actually sending an email? DI makes this straightforward:

var mockEmailService = new Mock<IEmailService>();
var orderService = new OrderService(mockEmailService.Object);
// Now you can test without sending real emails.

DI allows you to inject mock objects into your classes, making testing isolated, fast, and reliable.

3. Following SOLID Principles

DI is a natural fit for developers who follow the SOLID principles of object-oriented design, particularly the D for Dependency Inversion Principle. By relying on interfaces and abstracting dependencies, DI keeps your code clean, modular, and easy to extend.

The Curse: Why Some Developers Hate DI in .NET

However, not everyone’s in love with DI. Some developers argue that DI complicates code unnecessarily, especially for smaller projects or simpler use cases. Let’s break down their points of frustration.

1. Overcomplicating Simple Projects

Imagine you’re building a small, straightforward .NET application. You add DI to follow best practices, but now your Startup.cs is filled with:

public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped<IEmailService, EmailService>();
    services.AddTransient<IOrderService, OrderService>();
    services.AddSingleton<ILoggerService, LoggerService>();
    // And the list keeps growing...
}

You’ve turned a simple app into a forest of service registrations, just for the sake of “best practices.”

For smaller projects, this can feel like overkill. Do you really need to decouple every small service and inject every class? Probably not.

2. The ‘Magical’ Hidden Dependencies

One of the most common complaints about DI is the hidden dependencies. When you use DI heavily, you might not know what dependencies a class has until you look at the constructor, or worse, the service registrations in Startup.cs.

Let’s say you see this in your controller:

public class ProductsController : ControllerBase
{
    private readonly IProductService _productService;

    public ProductsController(IProductService productService)
    {
        _productService = productService;
    }

    // Actions here...
}

Wait, what services are actually being injected? How do you know what’s registered in the IOC container? It can feel like magic — which sounds fun but often leads to confusion and hunting through layers of configuration files to understand what’s really happening.

The Dark Side: DI Anti-Patterns in .NET

Where things really start to go wrong is when developers fall into some common DI anti-patterns. These practices can turn DI from a helpful tool into a real curse.

1. Over-Injection: Constructor Hell

Ever opened a class and found a constructor with five, six, or more dependencies?

public MyService(IDep1 dep1, IDep2 dep2, IDep3 dep3, IDep4 dep4, IDep5 dep5)
{
    // Yikes, that’s a lot of dependencies!
}

When classes have too many dependencies, it’s a sign that they’re doing too much. This is often referred to as the “constructor hell” — where classes are overwhelmed with too many injected services. At this point, your code becomes harder to read, test, and maintain.

2. Service Locator Anti-Pattern

When developers try to retrieve services from the IOC container manually, it’s called the Service Locator anti-pattern. This defeats the whole purpose of DI:

public class MyService
{
    private readonly IServiceProvider _serviceProvider;

    public MyService(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public void DoSomething()
    {
        var dep = _serviceProvider.GetService<IDependency>();
        // You are back to tightly coupled code...
    }
}

This essentially bypasses the inversion of control and brings back tight coupling!

3. Overuse of Singleton Services

Some developers love to make everything a singleton:

services.AddSingleton<IService, Service>();

While singleton can be useful for certain services (like logging), overusing it can lead to state-sharing issues. Singleton services maintain state throughout the app’s lifecycle, which can lead to unpredictable behavior and subtle bugs.

But Wait! There’s Hope: DI Done Right

While DI may feel like a curse in certain situations, when done right, it’s a powerful tool that can make your code cleaner, more modular, and easier to manage. Here are some tips to make DI work for you:

1. Keep Your Classes Small and Focused

If you find yourself injecting more than 3–4 dependencies into a class, it’s time to refactor. Follow Single Responsibility Principle (SRP): keep your classes focused on one thing and consider breaking larger services into smaller ones.

2. Use Factories or Abstract Factories

When you need to inject many dependencies or have a complex setup, consider using a factory to simplify things:

public interface IServiceFactory
{
    IService CreateService();
}

public class ServiceFactory : IServiceFactory
{
    private readonly IServiceProvider _serviceProvider;

    public ServiceFactory(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public IService CreateService()
    {
        return _serviceProvider.GetRequiredService<IService>();
    }
}

This can help you avoid constructor hell and keep your DI neat.

3. Use DI Wisely in Small Projects

If you’re building a small project or a prototype, feel free to use constructor injection sparingly. Not every class needs to be injected through the IOC container. Sometimes, it’s okay to use new.

Final Verdict: Is DI a Curse or a Blessing?

So, is Dependency Injection a curse for .NET developers? It depends on how you use it.

Done right, DI can make your code flexible, maintainable, and testable.
Overused or misused, it can lead to unnecessary complexity and tightly-coupled code masked by a framework’s magic.

If you feel overwhelmed by DI, take a step back. Ask yourself if every class needs to be injected, or if you’re over-complicating things. Remember, DI is just a tool — how you wield it will determine whether it’s a curse or a blessing in your .NET projects.

What’s Your Take?

Have you faced the curse of Dependency Injection? Or do you love the flexibility it offers? Share your experiences (and frustrations!) in the comments below. Let’s start a conversation about how we can master DI together!