Glob include files based on project extension (VS) (dotnet#46702)

* Glob include files based on project extension (VS)

* Update Directory.Build.targets

* Update Directory.Build.targets

* Update Directory.Build.targets

Author: ViktorHofer

Directory.Build.targets

@@ -24,6 +24,14 @@
     <InformationalVersion Condition="'$(InformationalVersion)' == '' and '$(VersionSuffix)' == ''">$(ProductVersion)</InformationalVersion>
     <InformationalVersion Condition="'$(InformationalVersion)' == '' and '$(VersionSuffix)' != ''">$(ProductVersion)-$(VersionSuffix)</InformationalVersion>
   </PropertyGroup>
+  
+  <!-- The Default behavior in VS is to show files for the first target framework in TargetFrameworks property.
+       This is required to show all the files corresponding to all target frameworks in VS. -->
+  <ItemGroup Condition="'$(DefaultLanguageSourceExtension)' != '' and
+                        ('$(BuildingInsideVisualStudio)' == 'true' or '$(DesignTimeBuild)' == 'true')">
+    <None Include="$(MSBuildProjectDirectory)\**\*$(DefaultLanguageSourceExtension)"
+          Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder);@(Compile)" />
+  </ItemGroup>
 
   <!-- Packaging -->
   <ItemGroup Condition="'$(IsPackable)' == 'true'">
@@ -62,4 +70,4 @@
       <PackDependsOn />
     </PropertyGroup>
   </Target>
-</Project>
+</Project>

src/libraries/Directory.Build.targets

@@ -256,13 +256,6 @@
     </When>
   </Choose>
 
-  <!-- The Default behavior in VS is to show files for the first target framework in TargetFrameworks property.
-        This is required to show all the files corresponding to all target frameworks in VS. -->
-  <ItemGroup Condition="'$(BuildingInsideVisualStudio)' == 'true' or '$(DesignTimeBuild)' == 'true'">
-    <None Include="$(MSBuildProjectDirectory)\**\*.cs"
-          Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder);@(Compile)" />
-  </ItemGroup>
-
   <PropertyGroup>
     <SkipLocalsInit Condition="'$(SkipLocalsInit)' == '' and '$(MSBuildProjectExtension)' == '.csproj' and '$(IsNETCoreAppSrc)' == 'true' and ($([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', '$(NetCoreAppCurrent)')))">true</SkipLocalsInit>
   </PropertyGroup>