.net - 使用 System.DirectoryServices 时尝试访问已卸载的应用程序域

Question

我们已经实现了一个向 Active Directory 进行身份验证的成员资格提供程序，并且它使用 System.DirectoryServices。当在带有 webdev 服务器的 Visual Studio 2010 上的 ASP.Net MVC 3 应用程序中使用此成员资格提供程序时，我们有时(六分之一)在登录应用程序时会遇到异常。

System.IO.FileNotFoundException: Could not load file or assembly 'System.Web' or one of its dependencies. The system cannot find the file specified.
File name: 'System.Web' 
at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
at System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
at System.Reflection.RuntimeAssembly.LoadWithPartialNameInternal(AssemblyName an, Evidence securityEvidence, StackCrawlMark& stackMark)
at System.DirectoryServices.AccountManagement.UnsafeNativeMethods.IADsPathname.Retrieve(Int32 lnFormatType)
at System.DirectoryServices.AccountManagement.ADStoreCtx.LoadDomainInfo()
at System.DirectoryServices.AccountManagement.ADStoreCtx.get_DnsDomainName()
at System.DirectoryServices.AccountManagement.ADStoreCtx.GetGroupsMemberOfAZ(Principal p)
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroupsHelper()
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroups()

=== Pre-bind state information ===
LOG: DisplayName = System.Web (Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: System.Web | Domain ID: 2
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
Calling assembly : HibernatingRhinos.Profiler.Appender, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0774796e73ebf640.

调用程序集是 HibernatingRhinos.Profiler.Appender，因此在 log4net 配置中禁用探查器后，我们得到了真正的异常:

System.AppDomainUnloadedException: Attempted to access an unloaded appdomain. (Except   at System.StubHelpers.StubHelpers.InternalGetCOMHRExceptionObject(Int32 hr, IntPtr pCPCMD, Object pThis)
at System.StubHelpers.StubHelpers.GetCOMHRExceptionObject(Int32 hr, IntPtr pCPCMD, Object pThis)
at System.DirectoryServices.AccountManagement.UnsafeNativeMethods.IADsPathname.Retrieve(Int32 lnFormatType)
at System.DirectoryServices.AccountManagement.ADStoreCtx.LoadDomainInfo()
at System.DirectoryServices.AccountManagement.ADStoreCtx.get_DnsDomainName()
at System.DirectoryServices.AccountManagement.ADStoreCtx.GetGroupsMemberOfAZ(Principal p)
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroupsHelper()
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroups()

异常总是在同一个方法中抛出，但目前我们无法重现它，因为它是随机发生的，但大约是六分之一。但是，当使用 II 而不是内置的 Visual Studio 2010 Web 服务器时，我们不会遇到异常。

这可能与在 Visual Studio webdev 上下文中使用多个应用程序域时的竞争条件有关，但这只是猜测。我们真的很想知道问题的原因是什么，因为我们不想在生产环境中出现这些异常。

我们发现了 2 个类似的案例，但没有人找到真正的解决方案:

http://our.umbraco.org/forum/developers/extending-umbraco/19581-Problem-with-custom-membership-and-role-provider

http://forums.asp.net/t/1556949.aspx/1

2011 年 5 月 18 日更新

重现异常的最少代码量(在 asp.net mvc 中)，其中 userName 是您的 Active Directory 登录名。

using System.DirectoryServices.AccountManagement;
using System.Web.Mvc;

namespace ADBug.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            string userName = "nickvane";
            var principalContext = new PrincipalContext(ContextType.Domain);

            UserPrincipal userPrincipal = UserPrincipal.FindByIdentity(
                principalContext,
                IdentityType.SamAccountName,
                userName);

            if (userPrincipal != null)
            {
                PrincipalSearchResult<Principal> list = userPrincipal.GetAuthorizationGroups();
            }

            return View();
        }
    }
}

可惜，异常仍然是随机发生的，因此没有完全可重现的错误。

Answer 1

这是对我有用的(.Net 4):

而不是这个:

principalContext = new PrincipalContext(ContextType.Domain)

同时使用域字符串创建主体上下文:

例如

principalContext = new PrincipalContext(ContextType.Domain,"MYDOMAIN")

应该在 4.5 中修复。 请参阅评论，尚未修复，但添加第二个参数仍然可以作为解决方法。