In .NET Core, the IoC (Inversion of Control) container, also known as the Dependency Injection (DI) container, manages the instantiation and lifetime of services. There are three primary service lifetimes available: Transient, Scoped, and Singleton. Each of these lifetimes determines how long a service instance is maintained by the DI container and how it is reused across the application.
Transient
Lifetime: Very short.
Instantiation: A new instance is created each time the service is requested.
State Retention: Does not retain state between different requests.
Use Case: Suitable for lightweight, stateless services that do not need to share data or state across different parts of the application. For example, services that generate random numbers or timestamps.
Example:
services.AddTransient<IMyService, MyService>();
Performance: Typically has higher memory usage due to frequent instantiation but avoids issues related to state retention and multi-threading[1][2][4][5].
Scoped
Lifetime: Short, per individual scope or request.
Instantiation: A single instance is created and shared within the scope of a single request.
State Retention: Retains state within the scope of the request but not across different requests.
Use Case: Ideal for services that need to maintain state within a single request, such as database contexts in web applications where the same instance is reused throughout the request.
Example:
services.AddScoped<IMyService, MyService>();
Performance: Balances memory usage and state retention, making it suitable for scenarios where multiple components within a request need to share data[1][2][4][5].
Singleton
Lifetime: Long, for the entire application lifetime.
Instantiation: A single instance is created and shared across all requests and throughout the application's lifetime.
State Retention: Retains state across the entire application.
Use Case: Best for services that need to maintain state or configuration settings that are shared across the entire application, such as logging services or configuration managers.
Example:
services.AddSingleton<IMyService, MyService>();
Performance: Most memory-efficient in terms of instantiation but requires careful management of state and thread safety to avoi...
