我注意到了同一件事，请查看该框架的ms更新，几天前有更新，希望新的nuget软件包具有已安装.

I had noticed the same thing, please look at the ms updates for the framework, there was an update a few days ago that the newer nuget packages expect to have been installed.

您遇到的问题是nuget软件包与您的SDk不匹配，至少这就是我所拥有的.在Windows更新并安装了新的Core Runtime之后，Version = 3.1.1.0一切都很好

The issue you are having is that the nuget packages are not matching your SDk, at least that's what I had. After doing a windows update and installing the new Core Runtime, Version=3.1.1.0 all was okey