Add ProjectReference documentation with Aliases attribute

[Copilot]

The ProjectReference MSBuild item was undocumented despite having the same Aliases attribute support as the Reference item. This adds complete documentation for ProjectReference including its Aliases metadata.

Changes

• Added ProjectReference section to MSBuild items documentation
• Documented Aliases metadata for setting extern aliases on project references
• Added XML and C# examples showing multi-version library references

Example Usage

<ItemGroup>
  <ProjectReference Include="..\MyLibraryV1\MyLibrary.csproj" Aliases="LibV1" />
  <ProjectReference Include="..\MyLibraryV2\MyLibrary.csproj" Aliases="LibV2" />
</ItemGroup>

extern alias LibV1;
extern alias LibV2;

var instanceV1 = new LibV1::MyNamespace.MyClass();
var instanceV2 = new LibV2::MyNamespace.MyClass();

The documentation follows the existing pattern used for PackageReference and FrameworkReference items.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• learn.microsoft.com
  • Triggering command: /usr/bin/curl curl -s REDACTED ./docs/framework/data/adonet/sql/linq/find-the-maximum-value-in-a-numeric-sequence.md ./docs/framework/data/adonet/sql/linq/how-to-return-rowsets.md ./docs/framework/data/adonet/sql/linq/eliminate-duplicate-elements-from-a-sequence.md ethod.md ./docs/framework/data/adonet/sql/linq/how-to-generate-the-object-model-in-visual-basic-or-csharp.md -method.md ntertype-method.md (dns block)
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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[agocke]

@copilot the file I'd like to update is https://learn.microsoft.com/en-us/visualstudio/msbuild/common-msbuild-project-items?view=visualstudio

[Copilot]

@copilot the file I'd like to update is https://learn.microsoft.com/en-us/visualstudio/msbuild/common-msbuild-project-items?view=visualstudio

The file you mentioned is in a different repository (MicrosoftDocs/visualstudio-docs), not in this dotnet/docs repository. The current PR updates the .NET SDK MSBuild documentation at /docs/core/project-sdk/msbuild-props.md.

To update the Visual Studio MSBuild documentation at https://github.com/MicrosoftDocs/visualstudio-docs/blob/main/docs/msbuild/common-msbuild-project-items.md, I would need access to that repository. Should I create a separate PR in the visualstudio-docs repository, or would you like me to modify a different file in this repository?