Lingua Setup Guide

Irihi.Lingua — Avalonia i18n Setup & Usage Guide / 国际化搭建与使用指南

Overview / 概述

Irihi.Lingua is a Roslyn incremental source generator that converts .resx / .json resource files into strongly-typed IObservable<string?> properties at compile time, enabling automatic UI refresh on culture switch with Avalonia UI. This SKILL covers two parts: (A) setting up from scratch, and (B) adding new translation keys.

Irihi.Lingua 是一个 Roslyn 增量源生成器，在编译时将 .resx / .json 资源文件 转换为强类型的 IObservable<string?> 属性，配合 Avalonia UI 实现文化切换时自动 刷新 UI。本 SKILL 涵盖两部分：(A) 从零搭建，(B) 添加新翻译键值对。

Part 1: Setting Up Lingua from Scratch / 第一部分：从零搭建 Lingua

Step 1 — Install the NuGet Package / 步骤 1 — 安装 NuGet 包

Add the following to your target Avalonia project's .csproj:

在目标 Avalonia 项目的 .csproj 中添加：

<PackageReference Include="Irihi.Lingua" />

Or via CLI / 或通过 CLI：

dotnet add package Irihi.Lingua

One PackageReference is enough / 一个 PackageReference 即可：The package bundles both the runtime library (Irihi.Lingua.Core) and the source generator (Irihi.Lingua.Generator). The generator runs automatically during compilation — no extra configuration is needed. 该包同时包含运行时库（Irihi.Lingua.Core）和源生成器 （Irihi.Lingua.Generator），生成器自动随编译运行，无需额外配置。

If your project lives in a source-tree environment (e.g. a demo project), use ProjectReference instead:

如果项目处于源码环境中（demo 项目），请改用 ProjectReference：

<!-- Runtime library / 运行时库 -->
<ProjectReference Include="..\..\src\Irihi.Lingua.Core\Irihi.Lingua.Core.csproj" />

<!-- Source generator (key: OutputItemType + ReferenceOutputAssembly) -->
<!-- 源生成器（关键：OutputItemType + ReferenceOutputAssembly） -->
<ProjectReference Include="..\..\src\Irihi.Lingua.Generator\Irihi.Lingua.Generator.csproj"
                  OutputItemType="Analyzer"
                  ReferenceOutputAssembly="false" />

Step 2 — Create Resource Files / 步骤 2 — 创建资源文件

Place resource files under a project directory (e.g. Resources/). Naming convention:

资源文件放在项目目录下（如 Resources/），命名约定：

• Default / invariant culture / 默认/不变文化：{BaseName}.resx or {BaseName}.json
• Culture-specific variants / 特定文化变体：{BaseName}.{culture}.resx or {BaseName}.{culture}.json

RESX Format / RESX 格式

Resources/Strings.resx (default culture, usually English / 默认文化，通常是英文)：

<?xml version="1.0" encoding="utf-8"?>
<root>
  <data name="App_Title" xml:space="preserve">
    <value>My Application</value>
  </data>
  <data name="Greeting_Message" xml:space="preserve">
    <value>Hello!</value>
  </data>
  <data name="Switch_Language" xml:space="preserve">
    <value>Switch Language</value>
  </data>
</root>

Resources/Strings.zh-Hans.resx (Simplified Chinese / 简体中文)：

<?xml version="1.0" encoding="utf-8"?>
<root>
  <data name="App_Title" xml:space="preserve">
    <value>我的应用程序</value>
  </data>
  <data name="Greeting_Message" xml:space="preserve">
    <value>你好！</value>
  </data>
  <data name="Switch_Language" xml:space="preserve">
    <value>切换语言</value>
  </data>
</root>

JSON Format / JSON 格式

Resources/Strings.json (default culture / 默认文化)：

{
  "app": {
    "title": "My Application",
    "greeting": "Hello from JSON!"
  }
}

Resources/Strings.zh-Hans.json：

{
  "app": {
    "title": "我的应用程序",
    "greeting": "来自 JSON 的问候！"
  }
}

JSON flattening rule / JSON 扁平化规则：Nested objects are joined with underscores, e.g. app.title → app_title. Only string leaf values are extracted as keys; arrays, numbers, and booleans are ignored. 嵌套对象用下划线连接，如 app.title → app_title。仅 string 类型的叶子值 会被提取为键；数组、数字、布尔值会被忽略。

Step 3 — Register AdditionalFiles in .csproj / 步骤 3 — 在 .csproj 中注册 AdditionalFiles

The source generator discovers resource files through AdditionalFiles — they must be declared explicitly:

源生成器通过 AdditionalFiles 发现资源文件，必须显式声明：

<ItemGroup>
  <!-- List individually / 逐一列出 -->
  <AdditionalFiles Include="Resources\Strings.resx" />
  <AdditionalFiles Include="Resources\Strings.zh-Hans.resx" />

  <!-- Or use a glob to include everything / 或用通配符一次性包含所有 -->
  <AdditionalFiles Include="Resources\**\*.resx" />
  <AdditionalFiles Include="Resources\**\*.json" />
</ItemGroup>

Step 4 — Declare the Language Manager / 步骤 4 — 声明语言管理器（LanguageManager）

Create a partial class in your project and apply the [LinguaManager] attribute pointing to the base resource file:

在项目中新建一个 partial class，添加 [LinguaManager] 特性，指向基础资源文件：

using Irihi.Lingua;

namespace MyApp;

[LinguaManager("./Resources/Strings.resx")]
public partial class LanguageManager;

• The path is relative to the project root (the .csproj directory).

• Must be a partial class — the source generator completes the rest at compile time.

• A project can have multiple managers (e.g. one for RESX, one for JSON).

• 路径相对于项目根目录（.csproj 所在目录）

• 必须是 partial class — 源生成器在编译时补全剩余代码

• 一个项目可以有多个管理器（如分别管理 RESX 和 JSON）

JSON manager / JSON 管理器 (optional / 可选)：

namespace MyApp;

[LinguaManager("./Resources/Strings.json")]
public partial class JsonLanguageManager;

Step 5 — Write the View + ViewModel / 步骤 5 — 编写 View + ViewModel

ViewModel

using System.Globalization;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace MyApp.ViewModels;

public partial class MainViewModel : ObservableObject
{
    // Each resource key maps to an IObservable<string?> property
    // 每个资源键对应一个 IObservable<string?> 属性
    public IObservable<string?> AppTitle => LanguageManager.Instance.App_Title;
    public IObservable<string?> GreetingMessage => LanguageManager.Instance.Greeting_Message;
    public IObservable<string?> SwitchLanguageLabel => LanguageManager.Instance.Switch_Language;
}

For each key the generator creates / 生成器会为每个键创建： ① a LinguaKey static field in the Keys nested class / Keys 嵌套类中的 LinguaKey 静态字段、 ② an IObservable<string?> readonly property / IObservable<string?> 只读属性、 ③ the singleton Instance / 单例 Instance。

XAML (Stream-binding ^ approach / 流绑定 ^ 方式)

<Window xmlns="https://github.com/avaloniaui"
        xmlns:vm="using:MyApp.ViewModels"
        x:DataType="vm:MainViewModel"
        Title="{Binding AppTitle^}">

    <StackPanel Spacing="16" Margin="40">
        <TextBlock Text="{Binding AppTitle^}"
                   FontSize="18" FontWeight="Bold" />
        <TextBlock Text="{Binding GreetingMessage^}"
                   FontSize="14" />
        <Button Content="{Binding SwitchLanguageLabel^}" />
    </StackPanel>
</Window>

The ^ operator / ^ 操作符 binds to IObservable<T> stream properties; Avalonia automatically subscribes and updates the UI when values change. 用于绑定 IObservable<T> 流属性，Avalonia 自动订阅并在值变化时更新 UI。

XAML (TranslateExtension approach — no ViewModel wrapper needed / TranslateExtension 方式，无需 ViewModel 包装)

<Window xmlns="https://github.com/avaloniaui"
        xmlns:local="using:MyApp">

    <!-- Translate reads directly from the Keys nested class; no ViewModel required -->
    <!-- Translate 直接从 Keys 嵌套类取值，无需 ViewModel -->
    <TextBlock Text="{Translate {x:Static local:LanguageManager+Keys.Greeting_Message}}"
               FontSize="13" FontStyle="Italic" />
</Window>

TranslateExtension is auto-registered via [assembly: XmlnsDefinition("https://github.com/avaloniaui", "Irihi.Lingua.Extensions")] — no extra xmlns declaration is needed. TranslateExtension 已通过 [assembly: XmlnsDefinition("https://github.com/avaloniaui", "Irihi.Lingua.Extensions")] 自动注册，无需声明额外 xmlns。

XAML (FormatTranslateExtension — format strings + dynamic parameters / FormatTranslateExtension 方式，格式化字符串 + 动态参数)

<Window xmlns="https://github.com/avaloniaui"
        xmlns:local="using:MyApp">

    <StackPanel Spacing="8">
        <NumericUpDown Width="200" Name="page" Value="1" />

        <TextBlock>
            <TextBlock.Text>
                <FormatTranslate FormatKey="{x:Static local:LanguageManager+Keys.Page_Template}">
                    <!-- {0} = bound value from a control / 来自控件的绑定值 -->
                    <TranslateEntry Binding="{Binding #page.Value}" />
                    <!-- {1} = another localized key (nested translation) / 另一个本地化键（嵌套翻译） -->
                    <TranslateEntry Key="{x:Static local:LanguageManager+Keys.Greeting_Message}" />
                </FormatTranslate>
            </TextBlock.Text>
        </TextBlock>
    </StackPanel>
</Window>

Example resource template / 对应的资源模板示例："Page {0} {1}" → Chinese / 中文 "第{0}页 {1}"。TranslateEntry supports two kinds of parameters / TranslateEntry 支持两种参数：

• Key="..." — another LinguaKey (itself updates on culture switch) / 另一个 LinguaKey（自身也会随文化切换更新）
• Binding="..." — standard Avalonia binding (supports #controlName.Property etc.) / 标准 Avalonia 绑定（支持 #controlName.Property 等）

Part 2: Adding New Translation Keys / 第二部分：添加新的翻译键值对

RESX

1. Add a <data> element to the base file:

   在基础文件中添加 <data> 元素：

   <!-- Resources/Strings.resx -->
   <data name="New_Welcome" xml:space="preserve">
     <value>Welcome back!</value>
   </data>
   

2. Add the corresponding translation in each culture variant file:

   在每个文化变体文件中添加对应翻译：

   <!-- Resources/Strings.zh-Hans.resx -->
   <data name="New_Welcome" xml:space="preserve">
     <value>欢迎回来！</value>
   </data>
   

3. Rebuild / 重新编译 — the generator automatically extracts the new key and generates: 生成器自动提取新键，生成：

   • LanguageManager.Keys.New_Welcome — static LinguaKey / 静态 LinguaKey
   • LanguageManager.Instance.New_Welcome — IObservable<string?> property / IObservable<string?> 属性

4. Expose it in the ViewModel:

   在 ViewModel 中暴露：

   public IObservable<string?> NewWelcome => LanguageManager.Instance.New_Welcome;
   

5. Use it in XAML:

   在 XAML 中使用：

   <TextBlock Text="{Binding NewWelcome^}" />
   <!-- or / 或 -->
   <TextBlock Text="{Translate {x:Static local:LanguageManager+Keys.New_Welcome}}" />
   

JSON

1. Add a new string property at any nesting level in the JSON:

   在 JSON 中任意层级添加新 string 属性：

   // Resources/Strings.json
   { "app": { "footer": "Default Footer" } }
   

2. The key is flattened to app_footer. / 该键会被扁平化为 app_footer。

3. Add the corresponding translation in culture variant files. / 文化变体文件中添加对应翻译。

4. Rebuild / 重新编译 — subsequent steps are identical to RESX. / 后续步骤与 RESX 相同。

Part 3: Switching Culture at Runtime / 第三部分：运行时切换 Culture

Core API / 核心 API

Every generated LanguageManager implements ILinguaManager and exposes the following culture-related members:

每个生成的 LanguageManager 都实现了 ILinguaManager，提供以下与文化切换相关的成员：

Culture fallback chain / 文化回退链： zh-Hans-CN → zh-Hans → zh → InvariantCulture. Pass a specific culture name and the system automatically finds the closest match. 传入精确文化名后，系统自动查找最近的匹配。

Calling UpdateCulture Directly / 直接调用 UpdateCulture

// Switch to Simplified Chinese / 切换到简体中文
LanguageManager.Instance.UpdateCulture(new CultureInfo("zh-Hans"));

// Switch to Japanese / 切换到日语
LanguageManager.Instance.UpdateCulture(new CultureInfo("ja-JP"));

// Switch back to default (invariant culture) / 切换回默认（不变文化）
LanguageManager.Instance.UpdateCulture(CultureInfo.InvariantCulture);

After UpdateCulture is called / UpdateCulture 调用后：

• Stream binding ^ / 流绑定 ^ — Avalonia automatically receives new values and the UI refreshes immediately. / Avalonia 自动收到新值，UI 立即刷新。
• TranslateExtension — also responds automatically; no extra handling required. / 同样自动响应，无需额外处理。
• Current subscribers / 当前订阅者 — all observers subscribed via .Subscribe() to observable properties receive the new values. / 所有通过 .Subscribe() 订阅 observable 属性的观察者都会收到新值。

Note / 注意：If your project has multiple LanguageManagers (e.g. one for RESX and one for JSON), you must call UpdateCulture on each of them when switching cultures. 如果项目中有多个 LanguageManager（如 RESX + JSON 各一个），需要在切换文化时 对每个管理器都调用 UpdateCulture。

Listening to CultureChanges (Non-UI Scenarios / 非 UI 场景)

Subscribe to CultureChanges when you need to respond to culture switches in code (e.g. saving user preferences, logging, etc.):

当需要在代码中响应文化切换（如保存用户偏好、日志记录等）时，订阅 CultureChanges：

// Subscribe to culture changes / 订阅文化变更
IDisposable sub = LanguageManager.Instance.CultureChanges.Subscribe(culture =>
{
    Console.WriteLine($"Culture switched to: {culture.Name}");

    // You can save the user's language preference here
    // 可以在此保存用户语言偏好
    // Preferences.Set("app_culture", culture.Name);
});

// Unsubscribe (usually in Dispose)
// 取消订阅（通常在 Dispose 中）
// sub.Dispose();

CultureChanges is a BehaviorSubject-style observable / CultureChanges 是一个 BehaviorSubject 风格的 observable：

• Emits the current culture immediately on subscribe. / 订阅时立即收到当前文化。
• Emits on every UpdateCulture call thereafter (even if the culture value is the same). / 之后每次 UpdateCulture 时推送（即使文化值相同也会推送）。

Appendix: Core Type Reference / 附录：核心类型速查

FAQ / 常见问题

Q: Compilation error LINGUA001? / 编译后报 LINGUA001？ A: Check that the path in [LinguaManager] is correct (relative to .csproj) and that the file is included in AdditionalFiles. 检查 [LinguaManager] 中的路径是否正确（相对 .csproj），以及文件是否已添加到 AdditionalFiles。

Q: Compilation error LINGUA002 / LINGUA003? / 编译后报 LINGUA002/LINGUA003？ A: LINGUA002 = a culture is missing a key; LINGUA003 = a culture has an extra key. Ensure all culture variant files have exactly the same set of keys. LINGUA002 = 某个文化缺少某个键，LINGUA003 = 某个文化有多余键。确保所有文化变体 文件键名完全一致。

Q: UI doesn't update after culture switch? / 切换文化后 UI 没有更新？ A: Make sure ViewModel properties are exposed as IObservable<string?> and XAML bindings use the ^ operator. TranslateExtension responds to culture switches automatically. 确认 ViewModel 属性是通过 IObservable<string?> 暴露的，XAML 绑定使用了 ^ 操作符。如果使用 TranslateExtension，则自动响应文化切换。

Q: How are nested JSON keys named? / JSON 的嵌套键如何命名？ A: Hierarchy levels are joined with underscores: settings.display.theme → settings_display_theme. 层级用下划线连接：settings.display.theme → settings_display_theme。