异常详细信息：System.Security.Policy.PolicyException：无法获取所需的权限答案

【问题标题】：Exception Details: System.Security.Policy.PolicyException: Required permissions cannot be acquired异常详细信息：System.Security.Policy.PolicyException：无法获取所需的权限
【发布时间】：2020-11-05 22:40:52
【问题描述】：

来源错误：

在执行当前 Web 请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪来识别有关异常起源和位置的信息。

堆栈跟踪：

[PolicyException: Required permissions cannot be acquired.]
   System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) +7627475
   System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +57

[FileLoadException: Could not load file or assembly 'Oracle.DataAccess, Version=2.122.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0
   System.Reflection.Assembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +43
   System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +127
   System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +142
   System.Reflection.Assembly.Load(String assemblyString) +28
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +46

[ConfigurationErrorsException: Could not load file or assembly 'Oracle.DataAccess, Version=2.122.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +613
   System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +203
   System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +105
   System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +178
   System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +54
   System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) +600
   System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) +125
   System.Web.Compilation.BuildManager.CompileResourcesDirectory() +31
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +304

[HttpException (0x80004005): Could not load file or assembly 'Oracle.DataAccess, Version=2.122.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +58
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +512
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +729

[HttpException (0x80004005): Could not load file or assembly 'Oracle.DataAccess, Version=2.122.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9002835
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +85
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +333

【问题讨论】：

我正在尝试从 VS2010 迁移到 VS 2017 并且构建成功，但在浏览器中弹出上述错误

标签： c# .net oracle visual-studio iis-10

【解决方案1】：

您很可能只使用 Visual Studio 的内置服务器尝试过它，它没有像 IIS 那样牢记安全限制。您可以通过在 iis 中托管站点进行测试，或者在 vs 中创建一个新项目并在该项目中复制代码。看起来您的程序集加载在其中配置文件没有夜间访问权限。

选项 1：您可以尝试在 web.conifg 文件中设置信任级别来解决问题。

<system.web>
    <securityPolicy>
        <trust level="Full" />
    </securityPolicy>

...
</system.web>

选项 2：找到 oracle 程序集并授予程序集的权限

选项 3：在 Windows 资源管理器中打开 DLL 的属性。它可能被标记为被阻止，因为它是从 Internet 下载的。转到属性并单击“取消阻止”按钮，问题可能会解决。

参考链接：

https://social.technet.microsoft.com/Forums/lync/en-US/56004b3e-487d-472c-b644-72cee8537ea7/loading-dll-from-network-fails-caspol-doesnt-fix-problem?forum=winserverpowershell

【讨论】：