EDIT FIX - Reinstalling VS did not work, reinstalling windows then VS did the trick... we live in 2019 almost and this shit is required to get vs to work properly?
I created a .NET Standard Class library which it seems to point to 1.6, when i go to change it to 2.0, I dont see it in the list (see attached image)
Also attached is latest info from my machine and versions, I have installed both the .NET Core 2.2.1 x64/x86 SDKs and I have the .NET Full Framework 4.7.2
EDIT 1: how vs was installed
I had the very same problem, even went as far as reporting it to Microsoft. It only happens with a clean install, so people checking it on their long used and upgraded systems wouldn't be able to help.
But, after many desperate tries and giving up, I switched off the computer and fired it up next morning. And VS was working all right, with the 2.0 where it should be.
I know this isn't a proper, reliable and repeatable solution but maybe it'll spare the trouble of reinstalling everything for somebody... :-)
I just ran into this issue. Reinstalling the sdk and VS didn't help. The issue ended up being an incorrect order of paths in the System Path variable. As soon as I moved C:\Program Files\dotnet\ before C:\Program Files (x86)\dotnet\ VS was able to pickup the correct sdks.
来源：https://stackoverflow.com/questions/53709476/missing-net-standard-2-0-framework-with-latest-net-core-sdk-2-2-1-net-framew