Injecting pre-release versions into CSPROJ NuPkg generation - msbuild

Question

I'm using the new CSPROJ schema introduced in Visual Studio 2017.
Additionally, I use this to create a NuPkg for my assembly.
<PropertyGroup>
<GeneratePackageOnBuild>true</GeneratePackageOnBuild>
<PackageId>MyComponent</PackageId>
<Version>2.1.0</Version>
.
.
.
</PropertyGroup>
I'm using VSTS to build my solution and I'd like to use the build to control the package quality, by adding a pre-release designation to the tag. Something like this:
<Version>2.1.0$(VERSIONSUFFIX)</Version>
To yield package names such as:
MyComponent.2.1.0-alpha-12345.nupkg
MyComponent.2.1.0-beta-67890.nupkg
MyComponent.2.1.0.nupkg
This works ok, but I found a nasty side effect - if I edit the version number interactively in Visual Studio it strips the $(VERSIONSUFFIX) placeholder. The only way I can update the version number is to edit the CSPROJ directly.
Is there a better way of allowing the build to control the NuPkg generation?
Thanks
-John

Answer 1

The editor will always change Version and remove all customisations.
The suggested way of the new SDK is to set VersionPrefix in the build and VersionSuffix - if set - will be appended to it.
So you'd have
<VersionPrefix>1.2.3</VersionPrefix>
and could build using -p:VersionSuffix=beta-123 to produce a 1.2.3-beta-123.nupkg file.
But editing in VS properties becomes impossible in any way.

Answer 2

You can use build variables to specify the package version and prefix version in NuGet pack task as you need.
If you want to use assembly version for the package version and change the prefix version as you want, you can use below steps:
1. Get assembly version
You can add the task Assembly Info Reader, then you can get the assembly version by the variable $(ASSEMBLYINFO.ASSEMBLYVERSION).
2. Define package version and prefix version as you need
You can define a variable in your build definition to specify the prefix version only. Such as the variable ver with the prefix part beta-1.1.
Add a PowerShell task to combine $(ASSEMBLYINFO.ASSEMBLYVERSION) and the prefix version together for packing nuget package. The PowerShell script can be:
Write-Host "##vso[task.setvariable variable=ver]$(ASSEMBLYINFO.ASSEMBLYVERSION)-$(ver)"
So the variable $(ver) contains the version with prefix version.
3. Specify the defined version with prefix for the package to be pack
In NuGet pack task, select Use an environment variable for Automatic package versioning option and specify ver as the Environment variable.
Then the packed package will as the format MyComponent.2.1.0-beta-1.1.nupkg etc.