.net framework 向下兼容吗？

先看图

我明明已经安装了4.7.1，结果打开4.6.2的项目让我降级到4.6.1.
请问这是怎么回事？高版本的框架还不能开发低版本项目吗？

I had this problem with VS 2017 15.5.7 on a new windows 10 laptop.

I closed VS, and opened a developer command prompt window and ran "devenv /resetuserdata"

I opened VS and waited for it to reconfigure itself.

Now I'm able to open existing Framework 4.7.1 solutions.

你只是安装了 .NET Framework Runtime。

Visual Studio 开发还需要安装对应的 Developer Pack，所以还需要另外下载安装。