Fix behavior for NET46 and NETCOREAPP2_0

src/Test/Utilities/Portable/Assert/UseCultureAttribute.cs

@@ -51,9 +51,12 @@ public UseCultureAttribute(string culture)
         /// <param name="uiCulture">The name of the UI culture.</param>
         public UseCultureAttribute(string culture, string uiCulture)
         {
-#if NET461 || NETCOREAPP20
+#if NET46 || NET461
             _culture = new Lazy<CultureInfo>(() => new CultureInfo(culture, useUserOverride: false));
             _uiCulture = new Lazy<CultureInfo>(() => new CultureInfo(uiCulture, useUserOverride: false));
+#elif NETCOREAPP2_0
+            _culture = new Lazy<CultureInfo>(() => new CultureInfo(culture));
+            _uiCulture = new Lazy<CultureInfo>(() => new CultureInfo(uiCulture));
 #else
             _culture = new Lazy<CultureInfo>(() => throw new NotSupportedException());
             _uiCulture = new Lazy<CultureInfo>(() => throw new NotSupportedException());
@@ -80,12 +83,14 @@ public override void Before(MethodInfo methodUnderTest)
             _originalCulture = CultureInfo.CurrentCulture;
             _originalUICulture = CultureInfo.CurrentUICulture;
 
-#if NET461 || NETCOREAPP20
-            Thread.CurrentThread.CurrentCulture = Culture;
-            Thread.CurrentThread.CurrentUICulture = UICulture;
+#if NET46 || NET461 || NETCOREAPP2_0
+            CultureInfo.CurrentCulture = Culture;
+            CultureInfo.CurrentUICulture = UICulture;
 
+#if NET46 || NET461
             CultureInfo.CurrentCulture.ClearCachedData();
             CultureInfo.CurrentUICulture.ClearCachedData();
+#endif
 #else
             throw new NotSupportedException("Cannot set the current culture on this framework target.");
 #endif
@@ -98,12 +103,14 @@ public override void Before(MethodInfo methodUnderTest)
         /// <param name="methodUnderTest">The method under test</param>
         public override void After(MethodInfo methodUnderTest)
         {
-#if NET461 || NETCOREAPP20
-            Thread.CurrentThread.CurrentCulture = _originalCulture;
-            Thread.CurrentThread.CurrentUICulture = _originalUICulture;
+#if NET46 || NET461 || NETCOREAPP2_0
+            CultureInfo.CurrentCulture = _originalCulture;
+            CultureInfo.CurrentUICulture = _originalUICulture;
 
+#if NET46 || NET461
             CultureInfo.CurrentCulture.ClearCachedData();
             CultureInfo.CurrentUICulture.ClearCachedData();
+#endif
 #else
             throw new NotSupportedException("Cannot set the current culture on this framework target.");
 #endif