调试期间出现异常后Visual Studio 2017需重启才能正常构建

问题还原 #

你在使用**Visual Studio 2017（15.7.1版本）**调试基于.NET Framework 4.6.2的WebApi项目时碰上个糟心事儿：调试时抛出异常后，再去构建项目就一堆MSB3061权限拒绝错误，说没法删除bin目录下的exe和dll文件，非得重启VS才能正常构建。你的项目还依赖了一个自定义类库，这个类库又用到了Entity Framework 6、AutoMapper和LinqKit。

错误日志片段如下：

1>Build FAILED. 1> 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\WebApiApplication.exe". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\WebApiApplication.exe' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\AutoMapper.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\AutoMapper.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\EntityFramework.SqlServer.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\EntityFramework.SqlServer.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\EntityFramework.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\EntityFramework.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.DataProtection.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.DataProtection.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Diagnostics.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Diagnostics.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Hosting.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Hosting.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Http.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Http.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Http.Abstractions.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Http.Abstractions.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Abstractions.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Abstractions.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Core.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Core.dll' is denied. 1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(5033,5): warning MSB3061: Unable to delete file "C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Razor.dll". Access to the path 'C:\PATH_TO_PROJECT_FOLDER\bin\Debug\net462\Microsoft.AspNetCore.Mvc.Razor.dll' is denied.

实用解决方案 #

我整理了几个经过开发者验证的解决办法，你可以按顺序试试：

1. 先杀残留进程（最快临时解决） #

调试异常后，VS经常没彻底关掉WebApi的宿主进程，这些进程会死死锁住bin目录里的文件。

• 打开任务管理器，找这两类进程：
  • 直接搜你的项目exe名（比如WebApiApplication.exe），找到就结束它
  • 如果用IIS Express调试，就找iisexpress.exe进程，把它结束掉
• 杀完进程再点构建，基本就能搞定，不用重启VS

2. 改下构建输出路径 #

有时候VS的文件监控机制会搞事情，换个输出路径可能就解锁了：

• 右键项目 → 属性 → 生成 → 输出路径，把默认的bin\Debug\net462改成别的，比如bin\Debug\net462_build
• 先清理解决方案，再重新构建，看看还会不会报错

3. 关掉“编辑并继续”功能 #

这个功能虽然方便，但偶尔会导致进程锁定文件，尤其是异常发生后：

• 点工具 → 选项 → 调试 → 常规，取消勾选启用编辑并继续
• 重启VS后再测试调试和构建流程

4. 升级VS2017到最新补丁 #

你用的15.7.1是比较早的版本，微软后续修复了不少调试和构建的bug：

• 打开VS的“工具 → 获取工具和功能”，检查并安装所有可用更新，尽量升到15.9.x以上的版本（VS2017最终版是15.9.56）

5. 检查自定义类库的资源泄漏 #

你的自定义类库依赖了EF6、AutoMapper这些组件，异常时可能没正确释放资源，导致文件被锁：

• 检查类库里有没有没关闭的数据库连接、文件流，确保异常时能通过using或者try-catch-finally释放资源
• 把AutoMapper和LinqKit更到兼容.NET4.6.2的最新稳定版，旧版本可能存在资源泄漏问题

最后总结 #

临时救急就杀进程，长期解决最好升级VS补丁，同时排查下类库的资源释放问题。如果这些都没用，你可以试试新建一个空白WebApi项目，逐步迁移代码和依赖，看看是不是原项目的配置文件坏了。

内容的提问来源于stack exchange，提问作者Michael Earls