Primary Constructor in C#

What is the primary constructor?

Primary constructors were introduced in .NET 8 and C# 12, a cleaner way of constructor initialization. We can use this syntax where we have a lot of constructor injections.

Understanding the Primary Constructor with Code

Let’s understand it with a simple example first before diving in depth. The older way of constructor injection:

public sealed class NewsletterService
{
    private readonly INewsletterRepository _newsletterRepository;

    public NewsletterService(INewsletterRepository newsletterRepository)
    {
        _newsletterRepository = newsletterRepository;
    }
}

This is how we can achieve the same with primary constructors:

internal class NewsletterService(INewsletterRepository newsletterRepository)
{
    public void Subscribe(string email)
    {
        newsletterRepository.Add(email);
    }
}

Pro(s) :

The following are the benefits of using primary constructors :

• It removes a lot of boilerplate code.

• Simplifies the syntax.

• Much more readability.