+semver:minor Replace retired BingTranslator with alternative on-the-fly localization

CHANGELOG.md

@@ -26,10 +26,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - BREAKING CHANGE: [L10NSharp] [L10NSharp.Windows.Forms] [SampleApp] [CheckOrFixXliff] [ExtractXliff] Replaced the `net461` target framework with `net462`. The `System.Resources.Extensions` version raised transitively by the `SIL.ReleaseTasks` upgrade (above) no longer ships a `net461`-specific assembly, so `net461` is no longer a supported or tested target. Projects that still need to target `net461` should continue using the last release built for it, or upgrade to at least `net462`.
 
+### Fixed
+
+- [L10NSharp.Windows.Forms] Fixed `LanguageChoosingDialog`'s fail-safe, on-the-fly translation of its title/message/OK button, which had been silently broken since the Bing/Microsoft Translator v1 SOAP API it used was retired. It now uses the free, keyless MyMemory Translation API by default; host apps that want more robust translation can opt in to the new public `MicrosoftTranslator` class (Azure AI Translator v3) by setting a subscription key. See [#163](https://github.com/sillsdev/l10nsharp/issues/163). The SampleApp has a "Show Language Chooser" button so you can see it in action without needing to fake a missing-locale scenario.
+
+### Removed
+
+- [L10NSharp.Windows.Forms] Removed the internal `BingTranslator` class and its generated WCF service reference, along with the `System.ServiceModel`/`System.Security.Cryptography.Xml` dependencies they required, since the API they called has been retired. See "Fixed", above.
+
 ### Security
 
 - [L10NSharp] [L10NSharp.Windows.Forms] [CheckOrFixXliff] [ExtractXliff] Upgraded `SIL.ReleaseTasks` from 2.5.0 to 3.3.0. This also raises the resolved version of `System.Resources.Extensions` (a transitive dependency of `SIL.ReleaseTasks`) from 6.0.0 to 10.0.11. Note: `SIL.ReleaseTasks` 3.3.0 has a known, build-time-only dependency on a vulnerable `Newtonsoft.Json` (via a temporary revert of its own `SIL.Core` dependency, pending an upstream `Mono.Unix` packaging issue) — per the upstream maintainers this is not an exploitable runtime risk, since the package is build-tool-only and never ships in L10nSharp's own output, and no L10nSharp or SIL.ReleaseTasks build step feeds it untrusted JSON. See [sillsdev/SIL.BuildTasks#88](https://github.com/sillsdev/SIL.BuildTasks/pull/88) for details.
-- [L10NSharp.Windows.Forms] Upgraded `System.ServiceModel.Http` and `System.ServiceModel.Primitives` from 6.2.0 to 8.1.2, and added a direct `System.Security.Cryptography.Xml` reference pinned to 8.0.4. `System.ServiceModel.Primitives` 8.1.2 resolves a vulnerable 8.0.2 of `System.Security.Cryptography.Xml` transitively on `net8.0-windows`; the direct reference overrides it with the latest patched 8.0.x release.
 
 ## [10.0.0] - 2026-08-27
 

src/L10NSharp.Windows.Forms.Tests/LanguageChoosingDialogViewModelTests.cs

@@ -139,7 +139,10 @@ public void TranslateStrings_RequestedCultureSpanishChokesOnFormatParam_Translat
 			Assert.AreEqual("No localization for Spanish (español)", model.Message);
 			var translator = new TestTranslatorSpanishChokesOnFormatParam();
 			model.TranslateStrings(translator);
-			// Note: the test translator mimics Bing's behavior of replacing the English name of the requested language with the word "English" in the translation.
+			// Note: this fake translator's "chokes on {0}, then swaps in the word 'English'" behavior mimics a quirk of the old,
+			// now-removed BingTranslator. It's kept as a synthetic worst case for the retry-without-format-param fallback path
+			// below; the current default translator, MyMemoryTranslator, doesn't exhibit either behavior (verified live: it
+			// preserves a literal "{0}" through translation, and translates rather than substitutes the language name).
 			Assert.AreEqual("No choke No localization for English (español)", model.Message);
 			Assert.AreEqual("No choke OK", model.AcceptButtonText);
 			Assert.AreEqual("No choke Choose a Language", model.WindowTitle);

src/L10NSharp.Windows.Forms.Tests/Translators/MicrosoftTranslatorTests.cs

@@ -0,0 +1,63 @@
+using System;
+using L10NSharp.Windows.Forms.Translators;
+using NUnit.Framework;
+
+namespace L10NSharp.Windows.Forms.Tests.Translators
+{
+	[TestFixture]
+	public class MicrosoftTranslatorTests
+	{
+		private const string kKeyEnvVar = "L10NSHARP_TRANSLATOR_KEY";
+		private const string kRegionEnvVar = "L10NSHARP_TRANSLATOR_REGION";
+
+		[TearDown]
+		public void TearDown()
+		{
+			MicrosoftTranslator.SubscriptionKey = null;
+			MicrosoftTranslator.Region = null;
+			Environment.SetEnvironmentVariable(kKeyEnvVar, null);
+			Environment.SetEnvironmentVariable(kRegionEnvVar, null);
+		}
+
+		[Test]
+		public void IsConfigured_NoKeySetAnywhere_ReturnsFalse()
+		{
+			Assert.That(MicrosoftTranslator.IsConfigured, Is.False);
+		}
+
+		[Test]
+		public void IsConfigured_SubscriptionKeySetDirectly_ReturnsTrue()
+		{
+			MicrosoftTranslator.SubscriptionKey = "some-key";
+			Assert.That(MicrosoftTranslator.IsConfigured, Is.True);
+		}
+
+		[Test]
+		public void IsConfigured_SubscriptionKeySetViaEnvironmentVariable_ReturnsTrue()
+		{
+			Environment.SetEnvironmentVariable(kKeyEnvVar, "some-key");
+			Assert.That(MicrosoftTranslator.IsConfigured, Is.True);
+		}
+
+		[Test]
+		public void SubscriptionKey_SetDirectly_TakesPrecedenceOverEnvironmentVariable()
+		{
+			Environment.SetEnvironmentVariable(kKeyEnvVar, "env-key");
+			MicrosoftTranslator.SubscriptionKey = "direct-key";
+			Assert.That(MicrosoftTranslator.EffectiveSubscriptionKey, Is.EqualTo("direct-key"));
+		}
+
+		[Test]
+		public void Region_NotSetDirectly_FallsBackToEnvironmentVariable()
+		{
+			Environment.SetEnvironmentVariable(kRegionEnvVar, "westus");
+			Assert.That(MicrosoftTranslator.EffectiveRegion, Is.EqualTo("westus"));
+		}
+
+		[Test]
+		public void Region_NeitherSet_IsNull()
+		{
+			Assert.That(MicrosoftTranslator.EffectiveRegion, Is.Null);
+		}
+	}
+}

src/L10NSharp.Windows.Forms/L10NSharp.Windows.Forms.csproj

@@ -9,14 +9,8 @@
     <SignAssembly>True</SignAssembly>
   </PropertyGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'net462' Or '$(TargetFramework)' == 'net48' ">
-    <Reference Include="System.ServiceModel" />
     <Reference Include="System.Windows.Forms" />
   </ItemGroup>
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net8.0-windows' ">
-    <PackageReference Include="System.ServiceModel.Http" Version="8.1.2" />
-    <PackageReference Include="System.ServiceModel.Primitives" Version="8.1.2" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="8.0.4" />
-  </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\L10NSharp\L10NSharp.csproj" />
   </ItemGroup>
@@ -74,8 +68,5 @@
       <LastGenOutput>Settings.Designer.cs</LastGenOutput>
       <Generator>SettingsSingleFileGenerator</Generator>
     </None>
-    <None Update="Service References\BingTranslatorService\Reference.svcmap">
-      <Generator>WCF Proxy Generator</Generator>
-    </None>
   </ItemGroup>
 </Project>