App instance redirection needs to fully support command line arguments (including current working directory, ideally exit code and deferral also)

[benstevens48]

I'm trying to port a single-instance UWP app to WindowsAppSDK. The app allows launching via the command line. Since command line launch is not explicitly supported with its own activated args in WindowsAppSDK, we have to use Environment.GetCommandLineArgs() or ILaunchActivatedEventArgs.Arguments get the command line arguments and Environment.CurrentDirectory to get the current working directory. ILaunchActivatedEventArgs.Arguments does work in a single app instance redirection scenario, but Environment.CurrentDirectory does not since it needs to be called in the original process where the command line was invoked. Also, it would be good to support deferring the exit of the command line launch and setting the exit code. Here are some possible solutions.

Idea 1

Add a string property CurrentDirectory to AppActivationArguments which can be easily marshalled during the app instance redirection.

Idea 2

Like idea 1 but instead allow an arbitrary data string to be set on AppActivationArguments like UserDataString allowing us to manually transfer the data. Could make this an object of some sort but then marshalling would be an issue presumably. Maybe a property UserData of type IBuffer would be the most general, since it needs to be serialized to bytes anyway.

Idea 3

Properly support CommandLineActivatedEventArgs (including GetDeferral and ExitCode).

Idea 4

In fact maybe GetDeferral and ExitCode are useful more generally in a redirection scenario, so you could go even more general and add a property like RedirectionEventArgs to AppActivationArguments. with perhaps the IBuffer from Idea 2 and maybe an ExitCode property or even a return buffer as well, and also with a GetDeferral method that would prevent RedirectActivationToAsync returning until completed.

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Without this, I guess I am going to have to create my own memory mapped file or something to transfer some info.

PS my app is packaged so I mainly care about that scenario, but I guess unpackaged should be supported as well.

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Note issue was updated to reflect below comment that command line args are actually available (but not current working directory).

[DHancock]

The command line args are available in the AppActivationArguments. You just need a bit of awkward casting:

       private void MainInstance_Activated(object? sender, AppActivationArguments e)
       {
           if (e.Kind == ExtendedActivationKind.Launch)
           {
               string args = ((ILaunchActivatedEventArgs)e.Data).Arguments;
               Debug.WriteLine($"args: {args}");
           }
       }

It works in packaged and unpackaged apps. I don't know about packaged via an execution alias though.

[benstevens48]

Thanks, that does appear to work. However, I also need to to know what the current working directory was when the command line was invoked. I will update the issue to reflect that.

[mominshaikhdev]

I don't think the root issue #1709 will ever be fixed anytime soon.

[benstevens48]

That's a related issue, but separate.