xaml-csharp-development-skill-for-avalonia

WinUI Activation (Protocol/File) and Lifecycle to Avalonia

Table of Contents

1. Scope and APIs
2. Concept Mapping
3. Conversion Example
4. Migration Notes

Scope and APIs

Primary WinUI APIs:

• AppInstance, AppActivationArguments, ExtendedActivationKind, protocol/file activation events

Primary Avalonia APIs:

• IClassicDesktopStyleApplicationLifetime, ControlledApplicationLifetimeStartupEventArgs, IActivatableLifetime, ProtocolActivatedEventArgs, FileActivatedEventArgs

Concept Mapping

WinUI idiom	Avalonia idiom
AppInstance activation event	IActivatableLifetime.Activated
ExtendedActivationKind.Protocol	ProtocolActivatedEventArgs
ExtendedActivationKind.File	FileActivatedEventArgs
Launch arguments at startup	Startup event + Args
App lifecycle hooks	desktop lifetime Startup/Exit/ShutdownRequested

Conversion Example

WinUI XAML:

<StackPanel Spacing="6">
  <TextBlock Text="Last activation:" />
  <TextBlock Text="{x:Bind ViewModel.LastActivation, Mode=OneWay}" />
</StackPanel>

WinUI C#:

AppInstance.GetCurrent().Activated += (_, e) =>
{
    switch (e.Kind)
    {
        case ExtendedActivationKind.Protocol:
            var protocol = (ProtocolActivatedEventArgs)e.Data;
            ViewModel.HandleUri(protocol.Uri);
            break;
        case ExtendedActivationKind.File:
            var files = (FileActivatedEventArgs)e.Data;
            ViewModel.HandleFiles(files.Files);
            break;
    }
};

Avalonia XAML:

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vm="using:MyApp.ViewModels"
             x:DataType="vm:ActivationViewModel">
  <StackPanel Spacing="6">
    <TextBlock Text="Last activation:" />
    <TextBlock Text="{CompiledBinding LastActivation}" />
  </StackPanel>
</UserControl>

Avalonia C#:

if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
{
    desktop.Startup += (_, e) => ViewModel.HandleStartupArgs(e.Args);
}

if (Application.Current?.TryGetFeature<IActivatableLifetime>() is { } activatable)
{
    activatable.Activated += (_, e) =>
    {
        if (e is ProtocolActivatedEventArgs protocol)
            ViewModel.HandleUri(protocol.Uri);
        else if (e is FileActivatedEventArgs file)
            ViewModel.HandleFiles(file.Files);
    };
}

Migration Notes

1. Keep activation parsing centralized so startup and re-activation share one code path.
2. Use typed activation event args in Avalonia instead of string-only command-line branching.
3. For desktop apps, combine startup args handling with optional IActivatableLifetime hooks.

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