I have the following variables defined:
Now once a build is complete (the last step in the build process), I want to update the VersionRevision variable, basically increment it.
So I'm looking for an API I can call from C# and create a console application or a powershell script to edit the build definition (if I have to do this)?
You can use VSTS Rest API to update the variable value in Build Definition. Both Console Application and Powershell Script is OK for this.
If I understand correctly, you want to get these build variables and them assignment them as your version number.
After the build completes, update and increment the VersionRevision. It's not a good way and seems not available to achieve it.
In TFS build there is a $(Rev:.r) which means
Use $(Rev:.rr) to ensure that every completed build has a unique name. When a build is completed, if nothing else in the build number has changed, the Rev integer value is incremented by one.
To version your assemblies you could just add an powershell script in your build definition, detail ways to achieve please follow this link from MSDN: Version your assemblies
And usually we only define and assignment variables with the Major and Minor version. If you want to change the value of them. You may need manually edit the build definition.
More related link about how to manage version numbers as part of your vNext builds.
