Csharp files of subprojects are not scanned by SonarQube

Ok, we’re getting lost here.

You have this

sonar.verbose=true
sonar.sourceEncoding=windows-1252
sonar.projectBaseDir=../..

Why cannot you change it to this?

/d:sonar.verbose=true
/d:sonar.sourceEncoding=windows-1252
/d:sonar.projectBaseDir=../..

Where /d:sonar.projectBaseDir is the key and ../.. is the value of key=value pair?

You don’t need to install command line tool. I’ve suggested to try to replace SonarQube Scanner for Azure DevOps v4.9 extension with older SonarQube Scanner for Azure DevOps v3.1 extension.

But that step might not be needed, because your screenshot looks way too different from my TFS 2015. This is what I see in my local instance:

Can you please try to describe your environment in more detail and verify what exact version are you using?

I have this in my TFS admin console:
Edition: Team Foundation Server 2015
Product Version: 14.114.28805.0 (Tfs2015.Update4.2)
Your screenshot looks like much more modern version.