如何将已经实例化的IOC容器传递给Asp.net 5应用程序？

Question

Using .Net core I have created a console application that self hosts an asp.net 5 for endpoint support (to receive notifications, health checks, etc...).

While reading about dependency injection in Asp.net 5 it shows how to use a custom IoC container, but it instantiates the container from within the Asp.net 5 ConfigureServices() method.

The problem this poses in a console application that also hosts an asp.net 5 application is that it appears that the WebHostBuilder instantiates a new instance of the Startup class, and while you can change which class is the "startup" class with .UseStartup<MySTartup>() you still can't control which instance of MyStartup Asp.net uses, which means there's no way to pass it an already setup container.

Is there a way (without using globals) to set up an IoC container and pass it to Asp.Net 5?

Answer 1

Ah, but you can. If I understand your problem correctly, this should provide the behavior you need:

When an ASP.NET 5 application starts, the Startup class is used to bootstrap the application, load its configuration settings, etc. (learn more about ASP.NET startup). However, if a class exists named Startup{EnvironmentName} (for example StartupDevelopment), and the ASPNET_ENV environment variable matches that name, then that Startup class is used instead.

http://docs.asp.net/en/latest/fundamentals/environments.html#startup-conventions

As for passing the container around, it's best to avoid that. As a last resort you can rely on the technique I used prior to working with DI-friendly frameworks: when bootstrapping the container instance at startup, use reflection to find IoC configurations in loaded assemblies, and call their methods, passing in the container.

Answer 2

Browsing Github, it appears like this is not possible. Asp.net 5 must always be the creator of the ioc container, and the only way to share an IOC container with the rest of the application is to grab it from IWebApplication.ApplicationServices property to be used in the rest of the app.

I raised a Github issue to hopefully get this resolved at some point.