Difference between Transient, Scoped, and Singleton type of dependency Injection in .NET CORE

Dependency injection (DI) is a fundamental concept in modern software development that promotes loose coupling and testability. In .NET applications, including those using ADO.NET for database operations, choosing the appropriate DI lifetime for your database-related services can greatly impact resource management and data consistency. In this blog post, we’ll explore how to use different dependency injection lifetimes — transient, scoped, and singleton.

1. Transient:

• Transient services are created each time they are requested.
• They are not shared among different parts of your application.
• A new instance is created every time you request the service from the DI container.
• This lifetime is suitable for stateless and lightweight services.

A transient lifetime is ideal for short-lived, stateless database operations where you create a new database connection for each operation. Here’s how to define it:

services.AddTransient<IMyService, MyService>();

Use Case: Transient services are suitable for stateless and lightweight services that don’t need to maintain any long-term state or shared data. They are created anew each time they are requested and disposed of when the scope gets completed. This makes them appropriate for services that can be short-lived and don’t store any state between method calls.

Examples:

• Logging services.
• Simple data processing services.
• Helper classes for one-time operations.

2. Scoped:

• Scoped services are created once per request (HTTP request in web applications).
• They are shared within the same scope during a single HTTP request, but different HTTP requests will have different instances.
• Scoped services are ideal for maintaining a state within a single HTTP request.

Scoped are suitable for maintaining a database connection or transaction for the duration of a single HTTP request in a web application. It ensures data consistency within that request. Here’s how to define it:

services.AddScoped<IMyService, MyService>();