HttpClient请求抛出IOException
HttpClient请求抛出IOException
提问于 2012-10-30 22:43:32
下面的代码抛出一个IOException，并显示消息：“指定的注册表项不存在。”
HttpClient client = new HttpClient();
Uri uri = new Uri("http://www.google.com");
client.GetAsync(uri);这只是Main中的一个控制台应用程序。看起来这个错误是由mscorlib.dll!Microsoft.Win32.RegistryKey.Win32Error(int errorCode抛出的(字符串字符串)。我不知道为什么抛出这个错误，也不知道如何开始调试它。
编辑堆栈跟踪：
at Microsoft.Win32.RegistryKey.Win32Error(Int32 errorCode，String str)
它只有一行代码，没有内部异常等等。
调用堆栈是：
mscorlib.dll!Microsoft.Win32.RegistryKey.Win32Error(int errorCode, string str) + 0x189 bytes
mscorlib.dll!Microsoft.Win32.RegistryKey.GetValueKind(string name) + 0x7f bytes
System.dll!System.Net.HybridWebProxyFinder.InitializeFallbackSettings() + 0x9e bytes
[Native to Managed Transition]
[Managed to Native Transition]
System.dll!System.Net.AutoWebProxyScriptEngine.AutoWebProxyScriptEngine(System.Net.WebProxy proxy, bool useRegistry) + 0xd0 bytes
System.dll!System.Net.WebProxy.UnsafeUpdateFromRegistry() + 0x2c bytes
System.dll!System.Net.Configuration.DefaultProxySectionInternal.DefaultProxySectionInternal(System.Net.Configuration.DefaultProxySection section) + 0x1d8 bytes
System.dll!System.Net.Configuration.DefaultProxySectionInternal.GetSection() + 0xec bytes
System.dll!System.Net.WebRequest.InternalDefaultWebProxy.get() + 0xcc bytes
System.dll!System.Net.HttpWebRequest.HttpWebRequest(System.Uri uri, System.Net.ServicePoint servicePoint) + 0xdf bytes
System.dll!System.Net.HttpWebRequest.HttpWebRequest(System.Uri uri, bool returnResponseOnFailureStatusCode, string connectionGroupName, System.Action<System.IO.Stream> resendRequestContent) + 0x2b bytes
System.Net.Http.dll!System.Net.Http.HttpClientHandler.CreateAndPrepareWebRequest(System.Net.Http.HttpRequestMessage request) + 0x59 bytes
System.Net.Http.dll!System.Net.Http.HttpClientHandler.SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) + 0xf4 bytes
System.Net.Http.dll!System.Net.Http.HttpMessageInvoker.SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) + 0x4f bytes
System.Net.Http.dll!System.Net.Http.HttpClient.SendAsync(System.Net.Http.HttpRequestMessage request, System.Net.Http.HttpCompletionOption completionOption, System.Threading.CancellationToken cancellationToken) + 0x13e bytes
System.Net.Http.dll!System.Net.Http.HttpClient.GetAsync(System.Uri requestUri, System.Net.Http.HttpCompletionOption completionOption) + 0xc bytes
ConsoleServiceTest.exe!ConsoleServiceTest.Program.Main(string[] args) Line 20 + 0x17 bytes C#
[Native to Managed Transition]
[Managed to Native Transition]
Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() + 0x5a bytes
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) + 0x285 bytes
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) + 0x9 bytes
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x57 bytes
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x51 bytes
[Native to Managed Transition] 回答 2
Stack Overflow用户
回答已采纳
发布于 2012-11-20 18:07:45
这似乎是由.NET框架的最新安全更新引起的：MS12-074: Vulnerabilities in .NET Framework could allow remote code execution: November 13, 2012 (KB 2745030)
这一切都归结为web代理解析中的以下代码：
[RegistryPermission(SecurityAction.Assert, Read=@"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework")]
private static void InitializeFallbackSettings()
{
allowFallback = false;
try
{
using (RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\.NETFramework"))
{
try
{
if (key.GetValueKind("LegacyWPADSupport") == RegistryValueKind.DWord)
{
allowFallback = ((int) key.GetValue("LegacyWPADSupport")) == 1;
}
}
catch (UnauthorizedAccessException)
{
}
catch (IOException)
{
}
}
}
catch (SecurityException)
{
}
catch (ObjectDisposedException)
{
}
}正如您所看到的，它会检查知识库文章中提到的特定注册表项。此外，您应该注意到异常是在内部捕获的，但您看到它是因为您已经在Visual Studio的调试选项中启用了First Chance exception。
如果不想看到此异常，则应使用值0添加指定的注册表项
Registry location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework
DWORD (32-bit) Value name: LegacyWPADSupport
Value data: 0对于64位计算机上的32位进程：
Registry location: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework
DWORD (32-bit) Value name: LegacyWPADSupport
Value data: 0Stack Overflow用户
发布于 2012-12-06 22:24:56
我同意Ligaz的回答，并且我记录了一个关于这个bug的连接问题：https://connect.microsoft.com/VisualStudio/feedback/details/773666/webrequest-create-eats-an-ioexception-on-the-first-call#details
将以下内容保存到.reg文件中并将其导入注册表，以防止引发此错误：
Windows Registry Editor Version 5.00
; The following value prevents an IOException from being thrown and caught
; by System.Net.HybridWebProxyFinder.InitializeFallbackSettings() (in System.dll)
; when WebRequest.Create is first called. By default the "LegacyWPADSupport"
; value doesn't exist, and when InitializeFallbackSettings calls GetValueKind,
; an IOException is thrown. This adds the value with its default of false to
; prevent the exception.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework]
"LegacyWPADSupport"=dword:00000000
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework]
"LegacyWPADSupport"=dword:00000000页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/13141434
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