Is there a simple way to pass additional parameters separate from string[] args to shared Application?

[cirrusone]

Say I have a shared project SomeProject.Shared which looks like this....

namespace SomeProject.Shared;

public partial class App : Application
{
    //....

    public override void OnFrameworkInitializationCompleted()
    {
        try
        {
            BindingPlugins.DataValidators.RemoveAt(0);
            if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
            {
		var args = desktop.Args; // Get args here
                desktop.MainWindow = new MainWindow() { DataContext = new MainViewModel() };

            }
            else if (ApplicationLifetime is ISingleViewApplicationLifetime singleViewPlatform)
            {
                throw new NotSupportedException("IClassicDesktopStyleApplicationLifetime only supported.");
            }

            base.OnFrameworkInitializationCompleted();
        }
        catch (Exception ex)
        {
            //Log.ForContext...
        }
    }

And then 3 different Projects, say SomeProject.Win, SomeProject.Mac and SomeProject.Lin as follows which pass args from the each project into the shared project

namespace SomeProject.Win;

static class Program
{
    [STAThread]
    public static void Main(string[] args) => BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);

    public static AppBuilder BuildAvaloniaApp()
        => AppBuilder.Configure<App>()
            .UsePlatformDetect()
#if DEBUG
        .LogToTrace()
#endif
        .WithInterFont();

}

Is there a way to pass additional parameters? I couldn't find an examples on how to do this, eg something like this...

    [STAThread]
    public static void Main(string[] args) => BuildAvaloniaApp().StartWithClassicDesktopLifetime(args, new SomeAdditionalClass());

I want to pass some custom data from each individual project into the shared project but thought manipulating the string[] args is potentially open to abuse.

[tobyfirth]

One possible way could be to use the overload of AppBuilder.Configure<App>(). The overload takes a Func<TApp> which would allow you to pass the extra args into the constructor of the App.

The code would look something like this

namespace SomeProject.Win;

static class Program
{
    [STAThread]
    public static void Main(string[] args) => BuildAvaloniaApp(new SomeAdditionalClass()).StartWithClassicDesktopLifetime(args);

    public static AppBuilder BuildAvaloniaApp(SomeAdditionalClass args)
        => AppBuilder.Configure<App>(() => new App(args))
            .UsePlatformDetect()
#if DEBUG
        .LogToTrace()
#endif
        .WithInterFont();

}

You could also use the AfterSetup() callback to set a property on the App class after it has been constructed which is called before OnFrameworkInitializationCompleted()

namespace SomeProject.Win;

static class Program
{
    [STAThread]
    public static void Main(string[] args) => BuildAvaloniaApp(new SomeAdditionalClass()).StartWithClassicDesktopLifetime(args);

    public static AppBuilder BuildAvaloniaApp(SomeAdditionalClass args)
        => AppBuilder.Configure<App>()
            .UsePlatformDetect()
           .AfterSetup(b => ((App)ab.Instance).Args = args)
#if DEBUG
        .LogToTrace()
#endif
        .WithInterFont();

}