ResXLocalization.Avalonia 1.1.0

ResXLocalization

Type-safe .resx localization for Avalonia and WPF - switch language live, no reload, no restart.

Localizing a XAML app with plain .resx usually means string-typed keys that break silently at runtime, and a language change that only takes effect after a restart. ResXLocalization fixes both: you keep the .resx files and editors you already use, and get compile-checked keys and instant, in-place language switching.

• ⚡ Live, no-reload language switching - set one property and every bound string updates in place.
• 🔒 Type-safe, compile-checked keys - a source generator turns every .resx into strongly-typed keys, so a renamed or deleted resource becomes a compile error, not a runtime surprise.
• 📦 Zero configuration - install the package and build; the source generator and MSBuild wiring are included.
• 🗂️ First-class multiple .resx support - look up by typed key, scope to one file, or search across all registered files.
• 🔤 Enum localization built in - localize enum members by naming convention.
• 🧮 Format arguments - Get(key, args…) formats in the active culture.
• 🩺 Missing-translation diagnostics - a visible, configurable !key! sentinel plus a TranslationNotFound event.
• 🌐 Language-picker ready - GetAvailableCultures() discovers the cultures your app actually ships.
• 🚀 Native AOT & trim clean (Avalonia package) - no reflection over your resources.

Requirements

• An app targeting .NET 8 or later, built with the .NET 8 SDK or later.
• For Avalonia: Avalonia 12. For WPF: Windows.
• .resx files with the standard sibling *.Designer.cs accessor, as generated by Visual Studio's or Rider's classic resx tooling (SDK-only GenerateResxSource accessors are not eligible).

Quick start

1. Add your strings

Add a .resx file the normal way - for example Resources/AppStrings.resx (your neutral/default language) - and a satellite file per culture, e.g. Resources/AppStrings.de.resx:

2. Build - typed keys are generated

On every build, the source generator emits a typed key class per .resx, named <FileName>Keys, in the same namespace as your resource file. Only string entries become keys.

// <auto-generated/> - for AppStrings.resx:
public static partial class AppStringsKeys
{
    public static readonly ResourceKey Greeting    = new("Greeting",    AppStrings.ResourceManager);
    public static readonly ResourceKey WindowTitle = new("WindowTitle", AppStrings.ResourceManager);
}

3. Register your resources at startup

using RentADeveloper.ResXLocalization;
using YourApp.Resources;

Localizer.Current.RegisterResourceManager(AppStrings.ResourceManager);
Localizer.Current.CurrentCulture = new CultureInfo("en");

4. Use it in XAML

<Window xmlns:l="clr-namespace:RentADeveloper.ResXLocalization.Avalonia;assembly=ResXLocalization.Avalonia"
        xmlns:res="clr-namespace:YourApp.Resources"
        Title="{l:Localize {x:Static res:AppStringsKeys.WindowTitle}}">

  <TextBlock Text="{l:Localize {x:Static res:AppStringsKeys.Greeting}}" />

</Window>

For WPF, map xmlns:l to the WPF assembly instead:

xmlns:l="clr-namespace:RentADeveloper.ResXLocalization.WPF;assembly=ResXLocalization.WPF"

5. Switch language - live

Localizer.Current.CurrentCulture = new CultureInfo("de");

Every {l:Localize} binding re-resolves immediately. No reload, no flicker.

Localizing enums

Add one string entry per enum member to your .resx, named Enum_<EnumTypeName>_<MemberName> - e.g. Enum_FileSortOrder_Ascending for FileSortOrder.Ascending. No attributes, no extra code.

In item templates (ComboBox, ListBox, …), where each item is the enum value, use {l:LocalizeEnum}:

<ComboBox.ItemTemplate>
  <DataTemplate>
    <TextBlock Text="{l:LocalizeEnum}" />
  </DataTemplate>
</ComboBox.ItemTemplate>

In code:

Localizer.Current.Get(FileSortOrder.Ascending);   // "Ascending (A-Z)" / "Aufsteigend (A-Z)"

A custom key prefix (KeyPrefix) and scoping to a single .resx file (ResourceManager) are supported, and LocalizeEnumConverter localizes enum values bound as data - see the full documentation.

Two packages, one engine

Both share the same UI-agnostic engine (ILocalizer / Localizer.Current, ResourceKey), the same source generator, and the same MSBuild wiring.

Documentation

The full documentation - lookup modes and fallback, enum localization, multiple .resx files, Native AOT publishing, troubleshooting, and complete runnable sample apps for both frameworks - lives in the project README; the API reference documents every type.

License

Released under the MIT License. © 2026 David Liebeherr.

Avalonia is a registered trademark of AvaloniaUI OÜ, used in the package name with written permission. This project is not affiliated with or endorsed by AvaloniaUI OÜ.