In this article, I will share my experiences and suggestions on using Dependency Injection in ASP.NET Core applications. The motivation behind these principles are;

• Effectively designing services and their dependencies.
• Preventing multi-threading issues.
• Preventing memory-leaks.
• Preventing potential bugs.

This article assumes that you are already familiar with Dependency Injection and ASP.NET Core in a basic level. If not, please read the ASP.NET Core Dependency Injection documentation first.

Basics

Constructor Injection

Constructor injection is used to declare and obtain dependencies of a service on the service construction. Example:

public class ProductService
{
    private readonly IProductRepository _productRepository;    public ProductService(IProductRepository productRepository)
    {
        _productRepository = productRepository;
    }    public void Delete(int id)
    {
        _productRepository.Delete(id);
    }
}

ProductService is injecting IProductRepository as a dependency in its constructor then using it inside the Delete method.

Good Practices:

• Define required dependencies explicitly in the service constructor. Thus, the service can not be constructed without its dependencies.
• Assign injected dependency to a read only field/property (to prevent accidentally assigning another value to it inside a method).

Property Injection

ASP.NET Core’s standard dependency injection container does not support property injection. But you can use another container supporting the property injection. Example:

using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstracti