找不到版本 4.0.0 的 Microsoft.CSharp 包 - UWP 构建失败

Question

我正在尝试在 VS2017 中创建包应用程序，但收到此错误：

The package Microsoft.CSharp with version 4.0.0 could not be found in C:\Users\User\.nuget\packages\, C:\Program Files (x86)\Microsoft 
SDKs\NuGetPackagesFallback\. Run a NuGet package restore to download the package.   Origami         

我谷歌并发现运行 nuget 命令

Install-Package Microsoft.CSharp -Version 4.0.0

我在 nuget 的控制台中成功运行此命令，输出如下：

    PM> Install-Package Microsoft.CSharp -Version 4.0.0
      GET https://api.nuget.org/v3/registration3-gz-semver2/microsoft.csharp/index.json
      OK https://api.nuget.org/v3/registration3-gz-semver2/microsoft.csharp/index.json 1403ms
    Restoring packages for D:\HoloLense\HoloLense Projects\HolographicAcademy-Holograms-101\Origami\App\Origami\project.json...
    Committing restore...
    Writing lock file to disk. Path: D:\HoloLense\HoloLense 
Projects\HolographicAcademy-Holograms-101\Origami\App\Origami\project.lock.json
    Restore completed in 546.94 ms for D:\HoloLense\HoloLense Projects\HolographicAcademy-Holograms-101\Origami\App\Origami\Origami.csproj.
    Executing nuget actions took 978.18 ms
    Time Elapsed: 00:00:06.6826674

但是当我尝试再次构建它时，我遇到了同样的错误。我缺少什么？