how to migrate global.asax event 'Application_Start' to program.cs on net.6?

Question

I try to migrate an old projet with a console app and a webservice ( both on .net framework 4.6) to a .net 6 console app (I want to suppress the ws and just have a service). On the old webservice I have a global.asax with a usefull event 'Application_Start' : it let me initialise a static class used for data access (code is in vb.net but I move to c#)

  Sub Application_Start(sender As Object, e As EventArgs)
        OldDLL.Initialisation(BmyEnum.Mode, My.Settings.mySCHEMAName)
    End Sub

I find various topics as (Migrate Global.asax to Startup.cs) on how to migrate from global.asax to Startup.cs but there is no more Startup.cs on my project generate by visualstudio2022, just a program.cs. Googleling a little bit I read that program.cs could replace startup.cs, using middleware. But I'm very new and it's a lot confusing. How I could in a simple way call OldDLL.Initialisation on program.cs ? Could be possible ( and how?) to embed my OldDll static on a service and inject it ? Thank you for reading, thank you for your suggestions.

Answer 1

in fact my projet is a vs2022 ASP.net core with react js projet. I found how to do: I create a service class to embed my dll:

public class OldDLLService:IOldDllService
{
    public OldDllService()
    {
        oldDLL.Initialisation();
    }
    
    public void DoSome()
    {
    //..
    }
}

And the interface playing with :

public interface IOldDllService
{
    void DoSome();
}

On programm.cs I injected the service :

builder.Services.AddSingleton<IOldDllService, OldDllService>();

var app = builder.Build();

And after can easy use for example in a controller:

public DummyController(ILogger<DummyController> logger, IOldDllService oldDllService)
{
 _logger = logger;
_oldDllService = oldDllService;

public void doSome()
{
 _oldDllService.DoSome();
}}