Missing .NET Standard 2.0:
I recently encountered an issue with Visual Studio 2017 fresh installation where in Project properties Target Framework was missing .NET Standard 2.0 and upper versions.
I solved the issue by installing the latest version of Visual Studio 2017. My current version was Visual Studio 2017 15.0.0 and it didn’t supported the later versions. So update was necessary.
Download latest version of Visual Studio 2017 using this link:
This will solve the issue. Thank You.