Localization with RESX Files · FmgLib.MauiMarkup

If your team already translates via .resx resource files (the classic .NET workflow), FmgLib.MauiMarkup plugs into them directly — same live-switching behavior as the JSON variant, driven by your ResourceManager.

1. Create the RESX Resources#

Add resource files to your project, e.g. under Resources/Languages:

Code

AppResources.resx          (default language)
AppResources.tr-TR.resx
AppResources.fr-FR.resx

Each file contains the same keys with translated values (Hello → "Hello World!" / "Merhaba Dünya!"). Visual Studio generates the AppResources class with a static ResourceManager.

2. Register in `MauiProgram.cs`#

builder
    .UseMauiApp<App>()
    .UseMauiMarkupLocalizationWithResx(AppResources.ResourceManager);

// or with an explicit startup language:
// .UseMauiMarkupLocalizationWithResx(AppResources.ResourceManager, "en-US");

// or with the options overload, for fallback culture / missing-key policy / culture sync:
// .UseMauiMarkupLocalizationWithResx(AppResources.ResourceManager, o => o
//     .UseDefaultCulture("en-US")
//     .OnMissingTranslation(MissingTranslationBehavior.Marker));

3. Bind Texts with `TranslateResx`#

new Label()
    .Text(e => e.TranslateResx("Hello"))
    .FontSize(32)
    .CenterHorizontal()
    .SemanticHeadingLevel(SemanticHeadingLevel.Level1),

new Label()
    .Text(e => e.TranslateResx(nameof(AppResources.Msg)))   // strongly-typed key!
    .FontSize(18)
    .CenterHorizontal()
    .SemanticDescription(e => e.TranslateResx("Msg"))

The nameof(AppResources.Msg) form is the recommended one — renaming a resource key becomes a compile-time-checked refactoring.

As with the JSON variant, any string property can be translated:

new Entry().Placeholder(e => e.TranslateResx(nameof(AppResources.EnterEmail)))
this.Title(e => e.TranslateResx(nameof(AppResources.SettingsTitle)))

4. Switch Languages at Runtime#

TranslatorResx.Instance.ChangeCulture(CultureInfo.GetCultureInfo("en-US"));

All TranslateResx-bound properties update immediately, and the call is safe from a background thread. As with the JSON variant, a culture change also updates the ambient CultureInfo by default — see CultureSyncMode.

Language selector example:

new VerticalStackLayout()
.Center()
.Children(
    new RadioButton()
        .IsChecked(TranslatorResx.Instance.CurrentCulture.Name == "tr-TR")
        .Content("tr-TR")
        .OnCheckedChanged((sender, e) =>
        {
            if (e.Value)
                TranslatorResx.Instance.ChangeCulture(CultureInfo.GetCultureInfo("tr-TR"));
        }),

    new RadioButton()
        .IsChecked(TranslatorResx.Instance.CurrentCulture.Name == "en-US")
        .Content("en-US")
        .OnCheckedChanged((sender, e) =>
        {
            if (e.Value)
                TranslatorResx.Instance.ChangeCulture(CultureInfo.GetCultureInfo("en-US"));
        })
)

Reading Translations in Code#

string msg = TranslatorResx.Instance[nameof(AppResources.Msg)];
await DisplayAlert("Info", msg, "OK");

// string extension equivalents:
string hello   = "Hello".ToTranslateResx();            // current culture
string helloTr = "Hello".ToTranslateResx("tr-TR");     // explicit culture

Notes & Tips#

Culture fallback follows standard ResourceManager rules: tr-TR → tr → default resources. Keep the neutral .resx complete. Setting UseFallbackCulture(...) adds one more attempt after that chain.
Missing keys return the key by default (previously ResourceManager.GetString returned null, which rendered an empty label). Change it with OnMissingTranslation(...) — the same policy as the JSON translator.
Persist the selection with Preferences and re-apply it at startup (see the pattern in Localization (JSON)).
JSON and RESX systems are independent (Translator vs. TranslatorResx); you can use both in one app, but standardizing on one keeps things simple.
Formatted strings: store the pattern in resources ("WelcomeUser" = "Welcome, {0}!") and bind it with TranslateResxFormat, which stays live for both the language and the values:

new Label().Text(e => e.TranslateResxFormat(nameof(AppResources.WelcomeUser), nameof(vm.UserName)))

Right to left: this.FlowDirection(e => e.FromCulture(TranslatorResx.Instance)) mirrors the page for Arabic/Hebrew.

Localization (JSON) — includes a JSON-vs-RESX comparison table
Fluent Properties

1. Create the RESX Resources#

2. Register in MauiProgram.cs#

3. Bind Texts with TranslateResx#

4. Switch Languages at Runtime#

Reading Translations in Code#

Notes & Tips#

Related Topics#

2. Register in `MauiProgram.cs`#

3. Bind Texts with `TranslateResx`#