I'm trying to build some UWP libraries and I receive this error:
D:\a\ZXing.Net.Xamarin\ZXing.Net.Xamarin\Source\ZXing.Net.Mobile.WindowsUniversal\ZXing.Net.Mobile.WindowsUniversal.csproj(155,3): error MSB4019: The imported project "C:\Program Files (x86)\MSBuild\Microsoft\WindowsXaml\v11.0\Microsoft.Windows.UI.Xaml.CSharp.targets" was not found. Confirm that the path in the declaration is correct, and that the file exists on disk.
The import clause in the .csproj file looks like this:
<Import Project="$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets" />
So I've tried to install the UWP workload programatically in the Windows2019 VM via chocolatey (both with this package and this other; not the Windows10SDK one because it gives an error when trying to install) with:
- run: |
choco install visualstudio2019-workload-universal
choco install visualstudio2019-workload-universalbuildtools
But this doesn't seem to cut it (the package gets installed successfully, apparently) because I still keep getting that compilation error.
Also tried including optional packages, to no avail:
choco install visualstudio2019-workload-universal --package-parameters "--includeOptional"
UPDATE: Turns out that my CI VM already had the file Microsoft.Windows.UI.Xaml.CSharp.targets, but it was located in C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Microsoft\WindowsXaml\v16.0 (and other versions of it in subfolders underneath this one). For more details, look at my answer.
Turns out that the VS2019 version installed in GithubActions VMs does already include UWP components (and others such as Xamarin.iOS, Xamarin.Android, Xamarin.Mac, etc); the problem was that my build was somehow defaulting to use an old version of MSBuild (the one located in C:/windows/Microsoft.NET/Framework/v4.0.30319/MSBuild.exe) that wasn't aware of these extensions.
As soon as I made sure that I used the version of MSBuild bundled with VS2019 (the one in %ProgramFiles(x86)%\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\MSBuild.exe) everything started to work again.
To fix it in my particular build I had to modify a build.cake file (IMO it might actually be a bug in CAKE to not detect the proper version of MSBuild by default...). If you want to take a look at the exact fix (that uses vswhere to locate MSBuild), it's this.