.NET 5发布后System.Security.Principal.Windows.dll缺失问题求助

我有一个包含多个项目的.NET 5解决方案，为实现Windows模拟功能，给其中一个项目添加了NuGet包System.Security.Principal.Windows。解决方案编译正常，调试时一切运行良好，但发布到文件系统后，System.Security.Principal.Windows.dll未被复制到发布目录。所有项目的目标框架均设置为net5.0-windows。

待发布项目的.csproj #

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

  <PropertyGroup>
    <TargetFramework>net5.0-windows</TargetFramework>
    <RollForward>Major</RollForward>
    <StartupObject>My.Special.Service.Program</StartupObject>
    <AssemblyVersion>7.0.0.0</AssemblyVersion>
    <FileVersion>7.0.0.42</FileVersion>
    <Version>7.0.0.42</Version>
  </PropertyGroup>
...
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <PlatformTarget>x64</PlatformTarget>
  </PropertyGroup>

  <ItemGroup>
    <SupportedPlatform Include="windows" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Authentication.Negotiate" Version="5.0.17" />
    <PackageReference Include="Microsoft.AspNetCore.Buffering" Version="0.2.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.17" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="5.0.17" />
    <PackageReference Include="Microsoft.Extensions.Hosting.WindowsServices" Version="5.0.1" />
    <PackageReference Include="Serilog.AspNetCore" Version="5.0.0" />
    <PackageReference Include="Serilog.Extensions.Logging.File" Version="2.0.0" />
    <PackageReference Include="Serilog.Sinks.Seq" Version="5.1.1" />
  </ItemGroup>
...
</Project>

依赖System.Security.Principal.Windows的项目的.csproj #

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

  <PropertyGroup>
    <TargetFramework>net5.0-windows</TargetFramework>
    <RollForward>Major</RollForward>
    <RootNamespace>My.Special.Service.ComAccess</RootNamespace>
    <AssemblyName>My.Special.Service.ComAccess</AssemblyName>
  </PropertyGroup>

  <ItemGroup>
    <SupportedPlatform Include="windows" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0" />
    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="6.0.0" />
    <PackageReference Include="System.Security.Principal.Windows" Version="5.0.0" />
  </ItemGroup>
...
</Project>

发布配置文件 #

<?xml version="1.0" encoding="utf-8"?>
<!--
https://go.microsoft.com/fwlink/?LinkID=208121. 
-->
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <DeleteExistingFiles>True</DeleteExistingFiles>
    <ExcludeApp_Data>False</ExcludeApp_Data>
    <LaunchSiteAfterPublish>True</LaunchSiteAfterPublish>
    <LastUsedBuildConfiguration>Release</LastUsedBuildConfiguration>
    <LastUsedPlatform>Any CPU</LastUsedPlatform>
    <PublishProvider>FileSystem</PublishProvider>
    <PublishUrl>bin\publish\Release</PublishUrl>
    <WebPublishMethod>FileSystem</WebPublishMethod>
    <SiteUrlToLaunchAfterPublish />
    <TargetFramework>net5.0-windows</TargetFramework>
    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
    <ProjectGuid>...</ProjectGuid>
    <SelfContained>false</SelfContained>
  </PropertyGroup>
</Project>

核心原因 #

当目标框架为net5.0-windows时，System.Security.Principal.Windows属于.NET 5 Windows平台的框架内置组件，你安装的NuGet包会被框架本身的版本替代。在非独立发布（SelfContained=false）模式下，框架相关DLL不会被复制到发布目录——.NET运行时会直接调用系统全局安装的框架文件。而调试时能正常运行，是因为VS开发环境会自动处理依赖加载逻辑。

解决方式1：强制复制依赖项 #

在依赖System.Security.Principal.Windows的项目（即My.Special.Service.ComAccess）的.csproj中，添加配置强制MSBuild将该DLL复制到输出目录：

<ItemGroup>
  <PackageReference Include="System.Security.Principal.Windows" Version="5.0.0">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
</ItemGroup>

或者更直接添加复制指令：

<ItemGroup>
  <Reference Include="System.Security.Principal.Windows">
    <Private>True</Private>
  </Reference>
</ItemGroup>

解决方式2：切换为独立发布模式 #

修改发布配置文件中的SelfContained属性为true，这样.NET运行时和所有依赖框架DLL都会被打包到发布目录：

<SelfContained>true</SelfContained>

注意：独立发布会增大包体积，但无需目标机器预先安装.NET 5运行时。

解决方式3：移除冗余NuGet包 #

对于net5.0-windows，Windows身份模拟相关API（如WindowsIdentity、WindowsImpersonationContext）已经内置在框架中，无需额外安装NuGet包。直接移除该包引用，改用框架内置类型即可解决问题。

内容的提问来源于stack exchange，提问作者sawie