Registering 32 bit COM Dll as part of a GitHub Actions Pipeline

I am trying to use github actions to deploy a dotnet app which has a dependency on at 32 bit COM Dll.

I register the DLl with RegSvr32, which seems to work. (I do not get an exception)

but then I get the following exception during the build:

Run msbuild path/to/my.csproj /p:Configuration=Release

MSBuild version 17.11.9+a69bbaaf5 for .NET Framework

C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(3040,5): warning MSB3284: Cannot get the file path for type library "0a67e301-3ecb-47be-bba9-dc67ff219358" version 1.0. Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED))

What worked for me was copying the dll to SysWow Directory:

- name: Copy DLL to SysWoW64
  run: |
    $dllPath = "${{ github.workspace }}\path\to\dllName.dll"
    $destinationPath = "$env:SystemRoot\SysWoW64\dllName.dll"
    Copy-Item -Path $dllPath -Destination $destinationPath -Force
    if (Test-Path $destinationPath) {
      Write-Output "DLL copied to $destinationPath"
    } else {
      Write-Error "Failed to copy DLL to $destinationPath"
      exit 1
    }


- name: Register COM DLL (32-bit)
  run: |
    $dllPath = "$env:SystemRoot\SysWoW64\DllName.dll"
    $outputFile = "${{ github.workspace }}\regsvr32_output.txt"
    Start-Process -FilePath "C:\Windows\SysWOW64\regsvr32.exe" -ArgumentList "/s", $dllPath -Wait -NoNewWindow -PassThru | Out-File $outputFile
    $exitCode = $LastExitCode
    Get-Content $outputFile

As an aside, you have to use msbuild if the project is referencing a COM dll.

- name: Set up MSBuild
  uses: microsoft/setup-msbuild@v1

# other steps ...

- name: Build and Publish
  run: msbuild path/to/ProjectName.csproj /t:Publish /p:Configuration=Release /p:OutputPath=./publish