VS2019 + Dotnet Framework 4.7.2中的Nuget包安装问题

Question

尝试在 .net framework 4.7.2 应用程序中安装 nuget 包时出现错误：

System.IO.IOException: The process cannot access the file 'D:\PP\packages\Newtonsoft.Json.12.0.2\lib\netstandard1.3\Newtonsoft.Json.dll' because it is being used by another process.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize)
   at System.IO.File.OpenFile(String path, FileAccess access, SafeFileHandle& handle)
   at System.IO.File.SetLastWriteTimeUtc(String path, DateTime lastWriteTimeUtc)
   at NuGet.Packaging.PackageFolderReader.CopyFiles(String destination, IEnumerable`1 packageFiles, ExtractPackageFileDelegate extractFile, ILogger logger, CancellationToken token)
   at NuGet.Packaging.PackageReaderBase.CopyFilesAsync(String destination, IEnumerable`1 packageFiles, ExtractPackageFileDelegate extractFile, ILogger logger, CancellationToken cancellationToken)
   at NuGet.Packaging.PackageExtractor.<ExtractPackageAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at NuGet.ProjectManagement.FolderNuGetProject.<>c__DisplayClass13_0.<<InstallPackageAsync>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at NuGet.Common.ConcurrencyUtilities.<ExecuteWithFileLockedAsync>d__2`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at NuGet.ProjectManagement.MSBuildNuGetProject.<InstallPackageAsync>d__36.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteInstallAsync>d__85.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__76.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__76.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__76.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__75.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__74.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at NuGet.PackageManagement.UI.UIActionEngine.<ExecuteActionsAsync>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at NuGet.PackageManagement.UI.UIActionEngine.<>c__DisplayClass12_0.<<PerformActionImplAsync>b__0>d.MoveNext()
Time Elapsed: 00:00:00.9362158
========== Finished ==========

环境。详情：

名称：包管理器主机
版本：5.4.0.6292
Visual Studio 2019 版本：16.4.5
应用版本：.Net Framework 4.7.2版

到目前为止尝试的步骤：

1. 我已重新启动机器并再次尝试，但仍然是同样的问题。
2. 能够在空白dotnet框架项目中成功安装nuget包。

Answer 1

进程无法访问文件'xxxxxxxNewtonsoft.Json.dll' 因为它正被另一个进程使用。

正如错误所说，nuget包由另一个进程控制。您可以尝试以下步骤：

1)先删除全局nuget缓存中C:\Users\xxx\.nuget\packages下的所有nuget包或使用clean nuget caches。

另外，删除解决方案路径下的packages 文件夹（如D:\PP\）。

2)关闭VS Instance，删除.vs隐藏文件夹、bin、obj文件夹。

3)如果你在进程资源管理器中找到msbuild.exe和devenv.exe，请杀死它们。

4)暂时禁用杀毒软件

5)在VS中重启你的项目，尝试第3步然后运行restore(右键解决方案-->Restore Nuget Packages)恢复安装的包然后尝试安装再次Newtonsoft.Json nuget 包。