How to change app language at runtime

Add two new pages to the Localization.Shared project by: Right-click on Localization.Shared > Add > New Item ... > Visual C# > XAML > Blank Page And, name them Page1 and LanguageSettings

Add some content to the two new pages:

• Page1.xaml:

  <Page x:Class="UnoLocalization.Page1" 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="Page1_Title" Text="Page one" FontSize="30" /> <Button x:Uid="Page1_GoBack" Content="Go back" Click="GoBack" /> </StackPanel> </Page> 

• Page1.xaml.cs:

  private void GoBack(object sender, RoutedEventArgs e) => Frame.GoBack(); 

• LanguageSettings.xaml:

  <Page x:Class="UnoLocalization.LanguageSettings" 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="LanguageSettings_Title" Text="Language Settings" FontSize="30" /> <Button Content="English" Click="SetAppLanguage" Tag="en" /> <Button Content="Français" Click="SetAppLanguage" Tag="fr" /> <Button x:Uid="LanguageSettings_GoBack" Content="Go back" Click="GoBack" Margin="0,12,0,0"/> </StackPanel> </Page> 

• LanguageSettings.xaml.cs:

  private void SetAppLanguage(object sender, RoutedEventArgs e) { if ((sender as Button)?.Tag is string tag) { // Change the app language Windows.Globalization.ApplicationLanguages.PrimaryLanguageOverride = tag; // Clear the back-navigation stack, and send the user to MainPage // This is done because any loaded pages (MainPage(in back-stack) and LanguageSettings (current active page)) // will stay in the previous language until reloaded. Frame.BackStack.Clear(); Frame.Navigate(typeof(MainPage)); } } private void GoBack(object sender, RoutedEventArgs e) => Frame.GoBack(); 

Add two new buttons to MainPage for navigation:

• MainPage.xaml:

  <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" /> <Button x:Uid="MainPage_GotoNextPage" Content="Next Page" Click="GotoNextPage" /> <Button x:Uid="MainPage_GotoLanguageSettings" Content="Language Settings" Click="GotoLanguageSettings" /> </StackPanel> 

• MainPage.xaml.cs:

  private void GotoNextPage(object sender, RoutedEventArgs e) => Frame.Navigate(typeof(Page1)); private void GotoLanguageSettings(object sender, RoutedEventArgs e) => Frame.Navigate(typeof(LanguageSettings)); 

Add a new folder fr under the Strings folder by: Right-click on String > Add > New Folder

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

Add the localization strings for the new elements: Open both Strings\en\Resources.resw and Strings\fr\Resources.resw, and add these: