都引用.NET标准类lib的.NET Windows窗体项目和UWP项目获得：

Question

1. I added both apps (framework 4.6.1) to same solution
2. added a .NET Standard 2.0 class library
3. referenced both apps to the class library.

...and get:

ERROR...

Error NU1201 Project .NET Standard VB ClassLibrary1 is not compatible with uap10.0.15063 (UAP,Version=v10.0.15063). Project .NET Standard VB ClassLibrary1 supports: netstandard2.0 (.NETStandard,Version=v2.0) UWP App1 C:\\PRIMARY\\WORK\\3 WindowsApp3\\UWP App1\\UWP App1.csproj 1

But the apps Target framework drop down only allows .NET Framework xxx
and the .NET Standard class library Target framework drop down only allows .NET Standard xx
so I can't make frameworks match.

(This is on Visual Studio 2017 Pro on Windows 10 Pro.)

All of the errors...

Here are the properties of the 2 app projects and the class lib project...

Answer 1

You need to set the Min Version of your UWP project to 16299 (or higher). Build 16299 was the first release that supports NET Standard 2.0. Earlier versions of UWP are not compatible as the error message points out.