.NET Core DI, ways of passing parameters to constructor

Question

Having the following service constructor

public class Service : IService
{
     public Service(IOtherService service1, IAnotherOne service2, string arg)
             


        

Answer 1

The expression parameter (x in this case), of the factory delegate is a IServiceProvider.

Use that to resolve the dependencies,

_serviceCollection.AddSingleton(x => 
    new Service(x.GetRequiredService(),
                x.GetRequiredService(), 
                ""));

The factory delegate is a delayed invocation. When ever the type is to be resolved it will pass the completed provider as the delegate parameter.