Razor无法识别Model及其他语法关键字问题排查

我们有一套自研CRM系统，基于旧版.NET Framework构建，混合了Web Forms与MVC Razor页面。目前正将其迁移至.NET 5，已完成所有基础设施项目（业务层、数据层等）到.NETStandard 2的转换。

转换完成后，所有开发人员在VS 2019和2022中，Razor页面的IntelliSense均无法识别Model和HtmlHelpers，升级前该功能完全正常。

问题截图：

更新后的csproj文件内容：

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="Current">
  <Import Project="..\packages\EntityFramework.6.4.4\build\EntityFramework.props" Condition="Exists('..\packages\EntityFramework.6.4.4\build\EntityFramework.props')" />
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <Import Project="..\packages\Microsoft.Data.SqlClient.SNI.5.0.1\build\net46\Microsoft.Data.SqlClient.SNI.targets" Condition="Exists('..\packages\Microsoft.Data.SqlClient.SNI.5.0.1\build\net46\Microsoft.Data.SqlClient.SNI.targets')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProductVersion>9.0.30729</ProductVersion>
    <SchemaVersion>2.0</SchemaVersion>
    <ProjectGuid>{B1B23E2B-2833-40D4-9E95-1515BAC57C63}</ProjectGuid>
    <ProjectTypeGuids>{349c5851-65df-11da-9384-00065b846f21};{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids>
    <OutputType>Library</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>CMPWare</RootNamespace>
    <AssemblyName>CMPWare</AssemblyName>
    <SccProjectName>
    </SccProjectName>
    <SccLocalPath>
    </SccLocalPath>
    <SccAuxPath>
    </SccAuxPath>
    <SccProvider>
    </SccProvider>
    <FileUpgradeFlags>
    </FileUpgradeFlags>
    <UpgradeBackupLocation>
    </UpgradeBackupLocation>
    <OldToolsVersion>2.0</OldToolsVersion>
    <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
    <TargetFrameworkProfile />
    <UseIISExpress>true</UseIISExpress>
    <IISExpressSSLPort>44336</IISExpressSSLPort>
    <IISExpressAnonymousAuthentication>
    </IISExpressAnonymousAuthentication>
    <IISExpressWindowsAuthentication>
    </IISExpressWindowsAuthentication>
    <IISExpressUseClassicPipelineMode>
    </IISExpressUseClassicPipelineMode>
    <UseGlobalApplicationHostFile />
    <NuGetPackageImportStamp>
    </NuGetPackageImportStamp>
    <Use64BitIISExpress />
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <Prefer32Bit>false</Prefer32Bit>
    <LangVersion>7.0</LangVersion>
    <PlatformTarget>AnyCPU</PlatformTarget>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <DebugType>full</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <DebugSymbols>true</DebugSymbols>
    <Prefer32Bit>false</Prefer32Bit>
    <LangVersion>7.0</LangVersion>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
  </PropertyGroup>
  <PropertyGroup>
    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">17.0</VisualStudioVersion>
    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Dev|AnyCPU'">
    <OutputPath>bin\</OutputPath>
    <LangVersion>7.0</LangVersion>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Live|AnyCPU'">
    <OutputPath>bin\</OutputPath>
    <LangVersion>7.0</LangVersion>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
  </PropertyGroup>
  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
  <Import Project="$(VSToolsPath)\WebApplications\Microsoft.WebApplication.targets" Condition="'$(VSToolsPath)' != ''" />
  <Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v17.0\WebApplications\Microsoft.WebApplication.targets" Condition="false" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
  <ProjectExtensions>
    <VisualStudio>
      <FlavorProperties GUID="{349c5851-65df-11da-9384-00065b846f21}">
        <WebProjectProperties>
          <UseIIS>True</UseIIS>
          <AutoAssignPort>True</AutoAssignPort>
          <DevelopmentServerPort>49771</DevelopmentServerPort>
          <DevelopmentServerVPath>/</DevelopmentServerVPath>
          <IISUrl>https://localhost:44301/</IISUrl>
          <NTLMAuthentication>False</NTLMAuthentication>
          <UseCustomServer>False</UseCustomServer>
          <CustomServerUrl>
          </CustomServerUrl>
          <SaveServerSettingsInUserFile>False</SaveServerSettingsInUserFile>
        </WebProjectProperties>
      </FlavorProperties>
    </VisualStudio>
  </ProjectExtensions>
  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
    <PropertyGroup>
      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
    </PropertyGroup>
    <Error Condition="!Exists('..\packages\EntityFramework.6.4.4\build\EntityFramework.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\EntityFramework.6.4.4\build\EntityFramework.props'))" />
    <Error Condition="!Exists('..\packages\EntityFramework.6.4.4\build\EntityFramework.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\EntityFramework.6.4.4\build\EntityFramework.targets'))" />
    <Error Condition="!Exists('..\packages\Microsoft.Data.SqlClient.SNI.5.0.1\build\net46\Microsoft.Data.SqlClient.SNI.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Microsoft.Data.SqlClient.SNI.5.0.1\build\net46\Microsoft.Data.SqlClient.SNI.targets'))" />
    <Error Condition="!Exists('..\packages\NETStandard.Library.2.0.3\build\netstandard2.0\NETStandard.Library.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NETStandard.Library.2.0.3\build\netstandard2.0\NETStandard.Library.targets'))" />
  </Target>
  <Import Project="..\packages\NETStandard.Library.2.0.3\build\netstandard2.0\NETStandard.Library.targets" Condition="Exists('..\packages\NETStandard.Library.2.0.3\build\netstandard2.0\NETStandard.Library.targets')" />
</Project>

内容的提问来源于stack exchange，提问作者geoff swartz