How to handle activation through files in WinUI 3 (Packaged)?

Question

I want to define a filetype to open in my app and have already gotten this far: I added this to my Package.appxmanifest inside the Application tag:

<Extensions>
  <uap:Extension Category="windows.fileTypeAssociation">
    <uap:FileTypeAssociation Name="pyrux-level">
      <uap:SupportedFileTypes>
        <uap:FileType>.prxlvl</uap:FileType>
      </uap:SupportedFileTypes>
      <uap:DisplayName>Pyrux Level</uap:DisplayName>
      <uap:EditFlags OpenIsSafe="true"/>
    </uap:FileTypeAssociation>
  </uap:Extension>
</Extensions>

This already registers the App as handler for the filetype and therefore opens it.

However, I am not sure how to handle the file once the app is open. I found a suggestion on the UWP documentation stating to use:

protected override void OnFileActivated(FileActivatedEventArgs args){}

However, I don't have a suitable method to override (guessing its due to the other API WinUI 3 uses compared to the normal UWP stuff...)

Can someone help me out on how to handle that event/figure out the path for the file opened? Thank you in advance!

Answer 1

According to the docs, instead of OnFileActivated, you use OnLaunched.

Can you try this?

using Microsoft.UI.Xaml;
using Microsoft.Windows.AppLifecycle;
using System.Linq;
using Windows.ApplicationModel.Activation;
using Windows.Storage;

namespace Example;

public partial class App : Application
{
    private Window? _window;

    public App()
    {
        this.InitializeComponent();
    }

    protected override void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs args)
    {
        AppActivationArguments appActivationArguments = AppInstance.GetCurrent().GetActivatedEventArgs();

        if (appActivationArguments.Kind is ExtendedActivationKind.File &&
            appActivationArguments.Data is IFileActivatedEventArgs fileActivatedEventArgs &&
            fileActivatedEventArgs.Files.FirstOrDefault() is IStorageFile storageFile)
        {
            // Do something with the file...
        }

        _window = new MainWindow();
        _window.Activate();
    }
}