How to use Windsor IoC in ASP.net Core 2

For others Reference In addition to the solution Nkosi provided.

There is a nuget package called Castle.Windsor.MsDependencyInjection that will provide you with the following method:

WindsorRegistrationHelper.CreateServiceProvider(WindsorContainer,IServiceCollection);

Which's returned type is IServiceProvider and you will not need to create you own wrapper.

So the solution will be like:

public class ServiceResolver{    
    private static WindsorContainer container;
    private static IServiceProvider serviceProvider;

    public ServiceResolver(IServiceCollection services) {
        container = new WindsorContainer();
        //Register your components in container
        //then
        serviceProvider = WindsorRegistrationHelper.CreateServiceProvider(container, services);
    }

    public IServiceProvider GetServiceProvider() {
        return serviceProvider;
    }    
}

and in Startup...

public IServiceProvider ConfigureServices(IServiceCollection services) {
    services.AddMvc();
    // Add other framework services

    // Add custom provider
    var container = new ServiceResolver(services).GetServiceProvider();
    return container;
}

For .net core, which centers DI around the IServiceProvider, you would need to create you own wrapper

Reference : Introduction to Dependency Injection in ASP.NET Core: Replacing the default services container

public class ServiceResolver : IServiceProvider {
    private static WindsorContainer container;

    public ServiceResolver(IServiceCollection services) {
        container = new WindsorContainer();
        // a method to register components in container
        RegisterComponents(container, services);
    }

    public object GetService(Type serviceType) {
        return container.Resolve(serviceType);
    }

    //...
}

and then configure the container in ConfigureServices and return an IServiceProvider:

When using a third-party DI container, you must change ConfigureServices so that it returns IServiceProvider instead of void.

public IServiceProvider ConfigureServices(IServiceCollection services) {
    services.AddMvc();
    // Add other framework services

    // Add custom provider
    var container = new ServiceResolver(services);
    return container;
}

At runtime, your container will be used to resolve types and inject dependencies.