Prism DI container from Android background service

Question

My app has a background service that may be run independently of the main app (HostApduService).

How can I access/use Prism's IContainer from this background service?

I am aware that IContainer is available from Xamarin.Forms.Application.Current, see:

https://tutel.me/c/programming/questions/45097342/implement+dependency+injection+in+background+services+in+xamarin+forms+using+prism

However it is possible in my case that the App doesn't exist, if the service is run without bringing up the app itself.

Answer 1

There are a couple options for you if App.Current is null.

1) in your background service initialize a new instance of the App:

var app = new App();
app.Container.Resolve<IMyService>();

2) use a helper method that only registers what you want and create the container you need for your background service:

public class App : PrismApplication
{
    protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {
        RegisterBackgroundServices(containerRegistry);
    }

    public static void RegisterBackgroundServices(IContainerRegistry containerRegistry)
    {
        // Register services you need in the Background Service
    }
}

public class MyBackgroundService
{
    IContainerExtension Container { get; }
    public MyBackgroundService()
    {
        // Note: Prism has some non-default Rules in place
        Container = new DryIocContainerExtension(new Container());
        App.RegisterBackgroundServices(Container);
    }
}