我在Visual Studio代码中遇到编译错误。每当我尝试构建项目时，它都会在终端中显示以下消息：

It was not possible to find any installed .NET Core SDKs
Did you mean to run .NET Core SDK commands? Install a .NET Core SDK from:
      https://aka.ms/dotnet-download

我认为问题与环境变量设置有关，但我真的不知道如何解决。实际上，在终端中，我看到了：

[local@localhost RazorPagesMovie]$ dotnet --info
  It was not possible to find any installed .NET Core SDKs
  Did you mean to run .NET Core SDK commands? Install a .NET Core SDK from:
      https://aka.ms/dotnet-download
Host (useful for support):
  Version: 3.1.5
  Commit:  c3rd789w23

.NET Core SDKs installed:
  No SDKs were found.
.NET Core runtimes installed:
  microsoft.AspNetCore.App 3.1.5 [/usr/lib64/dotnet/shared/microsoft.AspNetCore.App]
  microsoft.NETCore.App 3.1.5 [/usr/lib64/dotnet/shared/microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

但是安装了SDK：

local@localhost RazorPagesMovie]$ sudo dnf install dotnet-sdk-3.1
[sudo] password for local: 
Last metadata expiration check: 0:02:58 ago on Sat 04 Jul 2020 08:19:45 AM CEST.
Package dotnet-sdk-3.1-3.1.301-1.x86_64 is already installed.
Dependencies resolved.
Nothing to do.
Complete!

谢谢