>我有一个针对.net framework 4.8的vs 2013项目。我需要添加对 Microsoft.Extensions.Hosting nuget 包的引用，但当我这样做时，我在包管理器控制台上收到以下错误。
Error message:
PM> Install-Package Microsoft.Extensions.Hosting -Version 2.2.0
Installing 'Microsoft.Extensions.Hosting 2.2.0'.
You are downloading Microsoft.Extensions.Hosting from Microsoft, the license agreement to which is available at https://raw.githubusercontent.com/aspnet/AspNetCore/2.0.0/LICENSE.txt. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device.
Successfully installed 'Microsoft.Extensions.Hosting 2.2.0'.
Adding 'Microsoft.Extensions.Hosting 2.2.0' to QuartzExample.
Uninstalling 'Microsoft.Extensions.Hosting 2.2.0'.
Successfully uninstalled 'Microsoft.Extensions.Hosting 2.2.0'.
Install failed. Rolling back...
Install-Package : Could not install package 'Microsoft.Extensions.Hosting 2.2.0'. You are trying to install this package into
a project that targets '.NETFramework,Version=v4.8', but the package does not contain any assembly references or content
files that are compatible with that framework. For more information, contact the package author.
At line:1 char:1
+ Install-Package Microsoft.Extensions.Hosting -Version 2.2.0
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Install-Package], InvalidOperationException
+ FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand
我的项目文件如下所示
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import Project="$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props')" />
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>{07E02FE5-9E9B-434D-B6A2-D037DE7CE6CA}</ProjectGuid>
<OutputType>Exe</OutputType>
<AppDesignerFolder>Properties</AppDesignerFolder>
<RootNamespace>QuartzExample</RootNamespace>
<AssemblyName>QuartzExample</AssemblyName>
<TargetFrameworkVersion>v4.8</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>binDebug</OutputPath>
<DefineConstants>DEBUG;TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugType>pdbonly</DebugType>
<Optimize>true</Optimize>
<OutputPath>binRelease</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<ItemGroup>
<Reference Include="Quartz, Version=3.0.7.0, Culture=neutral, PublicKeyToken=f6b8c98a402cc8a4, processorArchitecture=MSIL">
<HintPath>..packagesQuartz.3.0.7libnet452Quartz.dll</HintPath>
<Private>True</Private>
</Reference>
<Reference Include="Quartz.Jobs, Version=3.0.7.0, Culture=neutral, PublicKeyToken=f6b8c98a402cc8a4, processorArchitecture=MSIL">
<HintPath>..packagesQuartz.Jobs.3.0.7libnet452Quartz.Jobs.dll</HintPath>
<Private>True</Private>
</Reference>
<Reference Include="Quartz.Plugins, Version=3.0.7.0, Culture=neutral, PublicKeyToken=f6b8c98a402cc8a4, processorArchitecture=MSIL">
<HintPath>..packagesQuartz.Plugins.3.0.7libnet452Quartz.Plugins.dll</HintPath>
<Private>True</Private>
</Reference>
<Reference Include="System" />
<Reference Include="System.Configuration" />
<Reference Include="System.Core" />
<Reference Include="System.Runtime.Remoting" />
<Reference Include="System.Xml.Linq" />
<Reference Include="System.Data.DataSetExtensions" />
<Reference Include="Microsoft.CSharp" />
<Reference Include="System.Data" />
<Reference Include="System.Xml" />
</ItemGroup>
<ItemGroup>
<Compile Include="MyJob.cs" />
<Compile Include="Program.cs" />
<Compile Include="PropertiesAssemblyInfo.cs" />
</ItemGroup>
<ItemGroup>
<None Include="App.config">
<SubType>Designer</SubType>
</None>
<None Include="packages.config" />
</ItemGroup>
<ItemGroup>
<Content Include="quartz_jobs.xml">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</Content>
</ItemGroup>
<Import Project="$(MSBuildToolsPath)Microsoft.CSharp.targets" />
<!-- 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>
-->
</Project>
我的应用配置如下
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section name="quartz" type="System.Configuration.NameValueSectionHandler, System, Version=1.0.5000.0,Culture=neutral, PublicKeyToken=b77a5c561934e089" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
</startup>
<quartz>
<add key="quartz.plugin.xml.type" value="Quartz.Plugin.Xml.XMLSchedulingDataProcessorPlugin, Quartz.Plugins" />
<add key="quartz.plugin.xml.fileNames" value="~/quartz_jobs.xml" />
</quartz>
</configuration>
在不更新 Visual Studio 2013 的情况下，是否可以添加对 .netstandard2 nuget 的引用，例如 Microsoft.Extensions.Hosting？
你不能。VS2013有一个古老的NuGet版本，它对.NET Standard一无所知，因此无法知道.NET Standard 2.0与.NET Framework 4.8兼容。
如果你真的无法升级到更新的Visual Studio，也许你可以看看.NET Core。Visual Studio Code是一个很小的安装，提供了良好的.NET开发体验，否则任何文本编辑器都可以，如果你不能使用支持Omnisharp的东西，你只会失去智能感。