我能够通过选中在 Visual Studio 中构建期间自动检查丢失的包"来解决此问题(允许 NuGet 下载丢失的包"已被选中)，然后重建.您可以在工具 --> NuGet 包管理器 --> 包管理器设置中找到这些设置.

I was able to resolve this by checking "Automatically check for missing packages during build in Visual Studio" (the "Allow NuGet to download missing packages" was already checked), then rebuilding. You can find these settings in Tools --> NuGet Package Manager --> Package Manager Settings.