“HttpClientHandler”不包含 net461 和 net47 中“ClientCertificates”的定义？

Question

我正在制作一个 NuGet 包，我的 csproj 如下所示：

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

  <PropertyGroup Label="Globals">
    <SccProjectName>SAK</SccProjectName>
    <SccProvider>SAK</SccProvider>
    <SccAuxPath>SAK</SccAuxPath>
    <SccLocalPath>SAK</SccLocalPath>
  </PropertyGroup>

  <PropertyGroup>
    <TargetFrameworks>netstandard2.0;netstandard1.6;net461;net47</TargetFrameworks>
    ...
    <PackageId>Package2</PackageId>
  </PropertyGroup>

  <ItemGroup>
    <ProjectReference Include="..\Package1\Package1.csproj" />
  </ItemGroup>

  <ItemGroup Condition="'$(TargetFramework)'=='net461' OR '$(TargetFramework)'=='net47'">
    <Reference Include="System.Net.Http" />
  </ItemGroup>

</Project>

它引用的项目如下所示：

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

  <PropertyGroup Label="Globals">
    <SccProjectName>SAK</SccProjectName>
    <SccProvider>SAK</SccProvider>
    <SccAuxPath>SAK</SccAuxPath>
    <SccLocalPath>SAK</SccLocalPath>
  </PropertyGroup>

  <PropertyGroup>
    <TargetFrameworks>netstandard2.0;netstandard1.6;net461;net47</TargetFrameworks>
    <PackageId>Package1</PackageId>
    ...
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)'=='Debug'">
    <NoWarn>1701;1702; CS1591</NoWarn>
  </PropertyGroup>

  <ItemGroup Condition="'$(TargetFramework)'=='netstandard1.6' OR '$(TargetFramework)'=='net461'">
      <PackageReference Include="System.ValueTuple" Version="4.5.0" />
  </ItemGroup>

  <ItemGroup Condition="'$(TargetFramework)'=='net461' OR '$(TargetFramework)'=='net47'">
    <Reference Include="System.Net.Http" />
  </ItemGroup>

</Project>

在Package2项目内部有以下行：

webRequestHandler.ClientCertificates.Add(certificate);

但它不是构建在net461or中net47，而是说：

'HttpClientHandler' does not contain a definition for 
'ClientCertificates' and no accessible extension method 
'ClientCertificates' accepting a first argument of type
'HttpClientHandler' could be found (are you missing a using
 directive or an assembly reference?) 

Package2(net461),
Package2(net47)

但我唯一改变的是从 package2 的 csproj 中删除它：

  <ItemGroup Condition="'$(TargetFramework)'=='netstandard2.0'">
    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="2.0.0" />
  </ItemGroup>

  <ItemGroup Condition="'$(TargetFramework)'=='netstandard1.6' OR '$(TargetFramework)'=='net461' OR '$(TargetFramework)'=='net47'">
    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="1.1.2" />
  </ItemGroup>

谁能帮助我了解如何修复它？我真的不想引入整个 NuGet 包只是为了修复这个依赖项，我认为我只是缺少一个程序集，但据我所知，它应该是System.Net.Http我应该已经引用的程序集（另一个也应该如此）它已经依赖的项目）。

Answer 1

看起来这个属性从版本 4.7.1 开始可用：

https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpclienthandler.clientcertificates?view=netframework-4.7.1

请注意，如果您选择较旧的 .NET 版本，您将看到如下消息：

The requested page is not available for .NET Framework 4.7.