Add build number to package version with `dotnet pack` in VSTS Build process - versioning

Question

With a .NET Framework library you could specify a version with a wildcard and NUGET pack command would append the build date and version automatically when running a NUGET Build Task in VSTS.
[assembly: AssemblyVersion("1.0.*")]
NUGET PACK would generate a NUPKG file with a version like 1.0.6604.1234 appending the date number and a build ID.
NET Standard issues
In .NET Core and .NET standard the new .csproj format does not support this wildcard format.
We can't package with Nuget.exe (reason: this issue) but we can use dotnet pack except I need to auto-increment the build numbers. The dotnet Build Task in VSTS allows me to wholly replace the version number, but I want to retain the version in the csproj file, and just append a build number (as I used to).
I found that using <VersionPrefix>x.y</VersionPrefix> in the csproj file would work with nuget pack and I could then add the additional parameter VersionSuffix=$(Build.BuildNumber) to the pack task.
All looked good until the first dev updated the project version in the project properties dialog. Visual Studio ignored the VersionPrefix and set the <Version> tag - and the build number fix is ignored because a Version tag exists.
Is there a way to read the Version from the csproj? If so I could set the build property to Version=$(ProjectVersion).$(Build.BuildNumber) ?
Or are there alternative ways to handle auto-incrementing the build version when packaging?

Answer 1

First you can select Use an environment variable for Automatic package versioning, use your defined variable such as temp ($(build.buildNumber)) as Environment variable.
More details take a look at this link: Dotnet pack automatic package versioning build number clarification
Another way is using the "arguments" field in the dotnet CLI task, you can pass additional arguments to the dotnet cli.
Using --version-suffix $(Build.BuildNumber) will pass the build
number as version suffix. Make sure you don't have a <version>
element set in your csproj, but rather a <versionprefix> element.
The built version will look like versionprefix-versionsuffix, so for
example, if you have <versionprefix>1.2.3</versionprefix> and build
number 201805002, the built version will be 1.2.3-201805002. In this case do not select the automatic package versioning.

Answer 2

Thanks to #patricklu-msft for his suggestions.
There is it appears no built-in way to emulate the wildcard behaviour we previously had NUGET pack with dotnet pack, nor was there way to get the <Version> tag out of the project file.
So I've created a new VSTS Build task that does this: VersionTaskReader in the MarketPlace.
This extension can be pointed to a .csproj or .vbproj and will set an environment variable VERSION, and VERSION_BUILD which has the BUILDID appended. You can optionally add a prefix to make each instance different if needed.
For example, if your project contains <Version>1.1</Version> then the VERSION_BUILD would be something like 1.1.8680
Then the dotnet pack task can use the environment variable VERSION_BUILD in the versioning options screen, so that the build number automatically increments.