将 Visual Studio 2019 更新到 16.4.0 后，我无法使用目标框架 2.2 运行测试

Question

我已经更新Visual studio 2019到版本 16.4.0。此版本包括.NET Core SDK3.1.100。

在那之后，我尝试在Target Framework2.2的项目中运行一些单元测试，但它无法这样做。它给出了以下错误：

Microsoft.VisualStudio.TestPlatform.ObjectModel.TestPlatformException: Testhost process exited with error: It was not possible to find any compatible framework version
The framework 'Microsoft.AspNetCore.App', version '2.2.0' was not found.
  - The following frameworks were found:
      3.1.0 at [C:\Program Files (x86)\dotnet\shared\Microsoft.AspNetCore.App]
You can resolve the problem by installing the specified framework and/or SDK.

如果我转到上述路径，我只找到了一个3.1.0 文件夹。如果我列出已安装的 SDKS，我会得到：

dotnet --list-sdks 
2.1.602 [C:\Program Files\dotnet\sdk]
2.1.700 [C:\Program Files\dotnet\sdk]
2.1.701 [C:\Program Files\dotnet\sdk]
2.1.801 [C:\Program Files\dotnet\sdk]
2.1.802 [C:\Program Files\dotnet\sdk]
2.2.100 [C:\Program Files\dotnet\sdk]
2.2.202 [C:\Program Files\dotnet\sdk]
2.2.207 [C:\Program Files\dotnet\sdk]
2.2.300 [C:\Program Files\dotnet\sdk]
2.2.301 [C:\Program Files\dotnet\sdk]
2.2.401 [C:\Program Files\dotnet\sdk]
2.2.402 [C:\Program Files\dotnet\sdk]
3.1.100 [C:\Program Files\dotnet\sdk]

如果我询问已安装的运行时，我会得到：

dotnet --list-runtimes
Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

所以，我看到 Microsoft.AspNetCore.App'，版本 '2.2.0' 安装在列出的运行时上。

另一方面，如果我这样做：Package Manager Console正在运行测试中单元测试项目上的“dotnet 测试” 。

我也Visual Studio Code安装了并且没有任何更改，我什至可以调试这些测试。

所以，我在这里有点迷茫，例如，我尝试从 C:\Program Files\dotnet\shared\ 手动复制 2.2.0 文件夹，但在那之后，我在尝试运行测试时遇到了其他错误。

任何人都可以帮助我或指出我正确的方向。

Answer 1

在查看@coloradoeos 的解决方案后，我发现了一种无需安装 x86 版本即可解决此问题的不同方法。

只需转到测试 > 任何 CPU 项目的进程架构 > x64

选择 x64 后，测试应正常运行。

Answer 2

我会向你推荐这个链接。

根本原因似乎是以下目录下缺少 x86 .NET Core 2.2 SDK 实例"C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App"。

我只有 3.1 版本，所以我特地下载了 2.2 SDK 的 x86 版本并安装了它。一旦我这样做了，testhost 就可以很好地从 Visual Studio (VS) 运行我的单元测试。我从来没有卸载过旧版本的SDK，所以这一定是框架/VS的更新过程有问题。