How to localize text resources

This guide will walk you through the necessary steps to localize an Uno Platform application.

Tip

The complete source code that goes along with this guide is available in the unoplatform/Uno.Samples GitHub repository - Localization

Tip

For a step-by-step guide to installing the prerequisites for your preferred IDE and environment, consult the Get Started guide.

Step-by-step instructions

1. Create a new Uno Platform application, following the instructions in Get Started guide.

2. Modify the content of MainPage:

   • In MainPage.xaml, replace the content of the page:

     <Page x:Class="UnoLocalization.MainPage"
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
           xmlns:toolkit="using:Uno.UI.Toolkit">
     
         <StackPanel toolkit:VisibleBoundsPadding.PaddingMask="Top">
             <TextBlock x:Uid="MainPage_IntroText" Text="Hello, world!" Margin="20" FontSize="30" />
             <TextBlock x:Name="CodeBehindText" Text="This text will be replaced" />
         </StackPanel>
     </Page>
     

     Note:

     • The x:Name is used to make the element accessible from the code-behind with that same name.
     • The x:Uid is used for localization. To localize a property, you need to add a string resource in each resource file using its x:Uid followed by a dot (.) and then the property name. eg: MainPage_IntroText.Text More on this in the resource steps that follow.

   • In MainPage.xaml.cs, add an Page.Loaded handler to change the text for CodeBehindText:

     public MainPage()
     {
         this.InitializeComponent();
         this.Loaded += (s, e) => CodeBehindText.Text = Windows.ApplicationModel.Resources.ResourceLoader
             .GetForViewIndependentUse()
             .GetString("MainPage_CodeBehindString");
     }
     

3. Create a new resource file for localization in French in the UnoLocalization.Shared project:

   1. Add a new folder fr under the Strings folder by: Right-click on Strings > Add > New Folder
   2. Add a new resource file Resources.resw under the fr folder by: Right-click on fr > Add > New Item ... > Visual C# > Xaml > Resources File

4. Add the localization strings for both English and French:

   Open both Strings\en\Resources.resw and Strings\fr\Resources.resw, and add these:

   Name	Value in en\Resources.resw	Value in fr\Resources.resw
   MainPage_IntroText.Text	Hello Uno	Bonjour Uno
   MainPage_CodeBehindString	String from code-behind	Texte provenant du code-behind

   Note

   Make sure to hit Ctrl+S for both files, to save the changes.

   Important

   The ResourceLoader will search for resources in the current language, then the default language. The default language is defined by the MSBuild property DefaultLanguage, which defaults to en.

5. You can now try to run the app.

   The "Hello World" text should be replaced with "Hello Uno", or "Bonjour Uno" if the targeted environment is on French culture. Now, if you change the language of the targeted PC or the mobile device AND restart the app, that text should also change accordingly.

   You can also set the starting culture to see the result, without having to modify the system language:

   • App.cs or App.xaml.cs:

     public App()
     {
         InitializeLogging();
         ChangeStartingLanguage();
     
         this.InitializeComponent();
         this.Suspending += OnSuspending;
     }
     
     private void ChangeStartingLanguage()
     {
         var culture = new System.Globalization.CultureInfo("fr");
     
         Windows.Globalization.ApplicationLanguages.PrimaryLanguageOverride = culture.TwoLetterISOLanguageName;
     }
     

6. For WinUI 3 projects

   • As an unpackaged WinUI 3 app doesn't contain a package.appxmanifest file, no further action is needed after adding the appropriate resources to the project.
   • If you are working with a packaged WinUI 3 app, open the .wapproj's package.appxmanifest in a text editor and locate the following section:

   <Resources>
       <Resource Language="x-generate"/>
   </Resources>
   

   Replace it with elements for each of your supported languages. For example:

   <Resources>
       <Resource Language="en-US"/>
       <Resource Language="es-ES"/>
       <!-- Add more languages as needed -->
   </Resources>
   

Get the complete code

See the completed sample on GitHub: LocalizationSamples/Localization

Additional Resources

Globalization and localization

Help! I'm having trouble

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Take a look at our common issues list if you're having any troubles.

If you are experiencing issues with Uno Platform, please visit our GitHub Discussions or Discord Server - where our engineering team and community will be able to help you.