Namespace Microsoft.Extensions.DependencyInjection

Provides types for configuring and managing dependency injection containers in .NET applications.

Summary of Members

Interfaces

Name	Description
IServiceCollection	Represents a collection of service descriptors that can be used to register services with a dependency injection container.
IServiceProvider	Represents an object that can provide services.
IServiceScope	Represents a scope that contains resolved services.
IServiceScopeFactory	Creates an `IServiceScope` which contains a resolved instance of the specified service.
ServiceDescriptor	Describes a service registration.

Classes

Name	Description
ServiceCollection	A default implementation of `IServiceCollection`.
ServiceManager	Represents a service container that can resolve services based on registered descriptors.

Extension Methods

Name	Description
Extension ServiceCollectionExtensions	Provides extension methods for adding services to an `IServiceCollection`.

Common Usage Patterns

The Microsoft.Extensions.DependencyInjection namespace is fundamental to modern .NET development, especially in ASP.NET Core and other host-based applications. Here are some common patterns:

Registering Services

You typically register services in an IServiceCollection. The extension methods on ServiceCollectionExtensions make this concise:


using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();

// Register a singleton service
services.AddSingleton<IMyService, MyService>();

// Register a scoped service
services.AddScoped<IAnotherService, AnotherService>();

// Register a transient service
services.AddTransient<IFoo, Foo>();

// Register a service with a factory
services.AddTransient<IBaz>(provider => new Baz(provider.GetRequiredService<ILogger<Baz>>()));

Building the Service Provider

Once services are registered, you build an IServiceProvider to resolve them:


var serviceProvider = services.BuildServiceProvider();

Resolving Services

You can resolve services from the IServiceProvider:


IMyService myService = serviceProvider.GetRequiredService<IMyService>();
IAnotherService anotherService = serviceProvider.GetService<IAnotherService>(); // Can return null

Scopes

For scoped services, you need to create an IServiceScope:


using (var scope = serviceProvider.CreateScope())
{
    var scopedService = scope.ServiceProvider.GetRequiredService<IAnotherService>();
    // Use scopedService within this scope
}