How to get an instance of IServiceProvider in .NET Core?

Question

IServiceProvider is an interface with single method:

object GetService(Type serviceType);

It\'s used to create instances of ty

Answer 1

Here is an updated approach:

var host = Host.CreateDefaultBuilder().ConfigureWebHostDefaults(builder =>
{
    builder.ConfigureAppConfiguration((hostingContext, config) =>
    {
        var env = hostingContext.HostingEnvironment;
        env.ContentRootPath = Directory.GetCurrentDirectory();
        env.EnvironmentName = "Development";
    });

    builder.UseStartup<Startup>();
}).Build();

Example usage:

host.Services.GetService<IFoo>();

Answer 2

First you need to install the Microsoft.Extensions.DependencyInjection NuGet package. (docs, API, API)

Then you create a new ServiceCollection and method chain it with the BuildServiceProvider method. In between that you can also register any service providers.

var serviceProvider = new ServiceCollection()
    .AddSingleton<IFooService, FooService>()
    .BuildServiceProvider();

Answer 3

You can find it in Program.cs

public static IServiceProvider ServiceProvider { get; private set; }

public static void Main(string[] args)
{
    IHost build = CreateHostBuilder(args).Build();
    ServiceProvider = build.Services;
    build.Run();
}

Answer 4

To get access to existing DI of ASP.NET Core application e.g. in some controller, you should register it in ConfigureServices method of Startup.cs:

public IServiceProvider ConfigureServices(IServiceCollection services)
{
   services.AddMvc();
   services.AddSingleton(services);   //  <- here

   // ... other DI registrations
   services.AddSingleton<IFooManager, FooManager>();
   services.AddTransient<IFooWorker, FooWorker>();
}

After that, you can use it in any resolved objects from DI like this:

public class FooManager: IFooManager
{
    private readonly ServiceProvider _di;

    public FooManager(IServiceCollection serviceCollection)
    {
        _di = serviceCollection.BuildServiceProvider();
    }

    public void Start()
    {
        var w1 = _di.GetRequiredService<IFooWorker>();  // new instance of FooWorker
        var w2 = _di.GetRequiredService<IFooWorker>();  // new instance of FooWorker
    }
}

Answer 5

As goaty mentioned it's enough to create new ServiceCollection. Here's example class which can be used to access DI container in .NET Core:

public static class ServiceProviderFactory
{
    public static IServiceProvider ServiceProvider { get; }

    static ServiceProviderFactory()
    {
        HostingEnvironment env = new HostingEnvironment();
        env.ContentRootPath = Directory.GetCurrentDirectory();
        env.EnvironmentName = "Development";

        Startup startup = new Startup(env);
        ServiceCollection sc = new ServiceCollection();
        startup.ConfigureServices(sc);
        ServiceProvider = sc.BuildServiceProvider();
    }
}

Startup class is taken from tested project so the service registrations don't need to be repeated.

Then in test class simply use:

var foo = ServiceProviderFactory.ServiceProvider.GetServices(typeof(IFoo));

Answer 6

This is the default implementation of IServiceCollection from Microsoft: https://github.com/aspnet/DependencyInjection/blob/master/src/DI/ServiceCollection.cs

Looking at the code then you should be able to get an IServiceCollection simply by calling:

var serviceCollection = new Microsoft.Extensions.DependencyInjection.ServiceCollection();

Hope that helps :)