MSB3268 .Net 4.0工程 引用BCL错误

Severity Code Description Project File Line Suppression State
Warning MSB3268 The primary reference "C:\Users\Administrator\.nuget\packages\microsoft.bcl.async\1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll" could not be resolved because it has an indirect dependency on the framework assembly "System.Threading.Tasks, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0". To resolve this problem, either remove the reference "C:\Users\Administrator\.nuget\packages\microsoft.bcl.async\1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll" or retarget your application to a framework version which contains "System.Threading.Tasks, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". HttpTest C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets 2106

在报错工程内添加配置文件

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="Plugins;"/>
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime" culture="neutral" publicKeyToken="b03f5f7f11d50a3a" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Threading.Tasks" culture="neutral" publicKeyToken="b03f5f7f11d50a3a"  />
        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>