VS2019（简单控制台应用程序） - 无法加载文件或程序集“System.Runtime.dll”或其依赖项之一

Question

这是一个普通的控制台应用程序，我已经在我的电脑上安装了NET.CORE，查看dotnet --info的结果

.NET SDK (reflecting any global.json):
 Version:   5.0.202
 Commit:    db7cc87d51

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19042
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.202\

Host (useful for support):
  Version: 5.0.5
  Commit:  2f740adc14

.NET SDKs installed:
  1.0.0-preview2-003131 [C:\Program Files\dotnet\sdk]
  3.1.408 [C:\Program Files\dotnet\sdk]
  5.0.102 [C:\Program Files\dotnet\sdk]
  5.0.104 [C:\Program Files\dotnet\sdk]
  5.0.202 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

这是我的项目文件，另外我找到了 System.Runtime.dll 的所有位置并将其包含到项目文件的路径。

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <RootNamespace>LinuxCamelCase</RootNamespace>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <ReferencePath>C:\Program Files\dotnet\sdk\3.1.408\;C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.14;C:\Program Files\dotnet\sdk\3.1.408\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\3.1.0\ref\netcoreapp3.1</ReferencePath>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <PlatformTarget>x64</PlatformTarget>
  </PropertyGroup>

    
  <ItemGroup>
    <PackageReference Include="MySqlConnector" Version="1.3.8" />
  </ItemGroup>

</Project>

但是在 Visual Studio 2019 中编译是不可能的。

1>J:\Vs2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2123,5): warning MSB3246: Resolved file has a bad image, no metadata, or is otherwise inaccessible. Could not load file or assembly 'System.Runtime.Intrinsics.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.

1>J:\Vs2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2123,5): warning MSB3246: Resolved file has a bad image, no metadata, or is otherwise inaccessible. Could not load file or assembly 'System.Runtime.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.
1>vbc : error BC30002: Type 'System.Void' is not defined.
1>vbc : error BC30002: Type 'System.Void' is not defined.
1>vbc : error BC30002: Type 'System.String' is not defined.
1>vbc : error BC30002: Type 'System.String' is not defined.
1>vbc : error BC30002: Type 'System.Void' is not defined.
1>vbc : error BC30002: Type 'System.Object' is not defined.
1>vbc : error BC30002: Type 'System.Object' is not defined.
1>vbc : error BC30652: Reference required to assembly '<Missing Core Assembly>, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' containing the type 'Object'. Add one to your project.
1>vbc : error BC30652: Reference required to assembly '<Missing Core Assembly>, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' containing the type 'Object'. Add one to your project.

dotnet-core-卸载

This tool cannot uninstall versions of the runtime or SDK that are 
    - SDKs installed using Visual Studio 2019 Update 3 or later.
    - SDKs and runtimes installed via zip/scripts.
    - Runtimes installed with SDKs (these should be removed by removing that SDK).
The versions that can be uninstalled with this tool are:

.NET Core SDKs:
  5.0.202  x64    [Used by Visual Studio. Specify individually or use --force to remove]
  5.0.104  x64
  3.1.408  x86
  3.1.408  x64
  1.0.1    x64    [Used by Visual Studio. Specify individually or use --force to remove]

.NET Core Runtimes:
  3.1.14  x64
  2.1.27  x64

ASP.NET Core Runtimes:
  5.0.5   x86
  5.0.5   x64
  3.1.14  x86
  2.1.27  x64

.NET Core Runtime & Hosting Bundles:

当然，我在安装VS2019时选择了.NET CORE开发。 但是现在我只有一个编译选项

<TargetFramework>net5.0</TargetFramework>

无法编译其他 framefork。为什么？

我不想从 NET 3.1 迁移到 NET 5.0，也不想在我的 Linux 托管环境中支持 NET CORE 5.0，因为我有很多历史应用程序，我不想要很多不同Linux 主机中的 NET CORE 版本。

我希望这只是错误而不是 Microsoft 政策 - 不允许开发人员保存首选版本的 NET CORE。

Answer 1

根据@sommmen 的说法，您是否启动了 Visual Studio 安装程序，单击了修改按钮，如下所示：

首先确保您选择了 .NET 桌面开发工作负载：

然后滚动到该页面的底部并选择 .NET Core 跨平台开发包，如下所示：

确保单击安装按钮并等待安装完成。这很有可能会解决您的问题。