Added CultureUI import

Author: dariatiurina

src/Components/WebAssembly/WebAssembly/src/Hosting/WebAssemblyCultureProvider.cs

@@ -3,6 +3,7 @@
 
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+using System.Linq;
 using System.Runtime.InteropServices.JavaScript;
 
 namespace Microsoft.AspNetCore.Components.WebAssembly.Hosting;
@@ -62,7 +63,7 @@ public virtual async ValueTask LoadCurrentCultureResourcesAsync()
             throw new PlatformNotSupportedException("This method is only supported in the browser.");
         }
 
-        var culturesToLoad = GetCultures(CultureInfo.CurrentCulture);
+        var culturesToLoad = GetCultures(CultureInfo.CurrentCulture).Union(GetCultures(CultureInfo.CurrentUICulture)).ToArray();
 
         if (culturesToLoad.Length == 0)
         {

src/Components/test/E2ETest/Tests/WebAssemblyLocalizationTest.cs

@@ -35,4 +35,23 @@ public void CanSetCultureAndReadLocalizedResources(string culture, string messag
         var messageDisplay = Browser.Exists(By.Id("message-display"));
         Assert.Equal(message, messageDisplay.Text);
     }
+
+    [Theory]
+    [InlineData("en-US", "fr-FR", "Bonjour!")]
+    [InlineData("fr-FR", "en-US", "Hello!")]
+    public void CanSetCultureAndDifferentiateBetweenCurrentAndUICulture(string culture, string cultureUI, string message)
+    {
+        Navigate($"{ServerPathBase}/?culture={culture}&cultureUI={cultureUI}");
+
+        Browser.MountTestComponent<LocalizedText>();
+
+        var cultureDisplay = Browser.Exists(By.Id("culture-name-display"));
+        Assert.Equal($"Culture is: {culture}", cultureDisplay.Text);
+
+        var cultureUIDisplay = Browser.Exists(By.Id("culture-ui-display"));
+        Assert.Equal($"CultureUI is: {cultureUI}", cultureUIDisplay.Text);
+
+        var messageDisplay = Browser.Exists(By.Id("message-display"));
+        Assert.Equal(message, messageDisplay.Text);
+    }
 }

src/Components/test/testassets/BasicTestApp/LocalizedText.razor

@@ -1,2 +1,3 @@
 <h3 id="culture-name-display">Culture is: @System.Globalization.CultureInfo.CurrentCulture.Name</h3>
+<h3 id="culture-ui-display">CultureUI is: @System.Globalization.CultureInfo.CurrentUICulture.Name</h3>
 <p id="message-display">@Resources.Message</p>

src/Components/test/testassets/BasicTestApp/Program.cs

@@ -63,6 +63,7 @@ private static void ConfigureCulture(WebAssemblyHost host)
     {
         // In the absence of a specified value, we want the culture to be en-US so that the tests for bind can work consistently.
         var culture = new CultureInfo("en-US");
+        var cultureUI = new CultureInfo("en-US");
 
         Uri uri = null;
         try
@@ -77,12 +78,18 @@ private static void ConfigureCulture(WebAssemblyHost host)
         if (uri != null && HttpUtility.ParseQueryString(uri.Query)["culture"] is string cultureName)
         {
             culture = new CultureInfo(cultureName);
+            cultureUI = culture; // Default to the same culture for UI if not specified
+        }
+
+        if (uri != null && HttpUtility.ParseQueryString(uri.Query)["cultureUI"] is string cultureUIName)
+        {
+            cultureUI = new CultureInfo(cultureUIName);
         }
 
         // CultureInfo.CurrentCulture is async-scoped and will not affect the culture in sibling scopes.
         // Use CultureInfo.DefaultThreadCurrentCulture instead to modify the application's default scope.
         CultureInfo.DefaultThreadCurrentCulture = culture;
-        CultureInfo.DefaultThreadCurrentUICulture = culture;
+        CultureInfo.DefaultThreadCurrentUICulture = cultureUI;
     }
 
     // Supports E2E tests in StartupErrorNotificationTest