UserPrincipal.GetGroups 失败，出现未知错误

Question

我正在尝试使用以下代码获取用户的所有 Active Directory 组：

    private static IEnumerable<string> GetGroupNames(string userName)
    {
        using (var context = new PrincipalContext(ContextType.Domain))
        {
            using (var userPrincipal = UserPrincipal.FindByIdentity(context, userName))
            {
                var groupSearch = userPrincipal.GetGroups(context);
                var result = new List<string>();
                foreach (var principal in groupSearch)
                {
                    Log.LogDebug("User {0} is member of group {0}", userPrincipal.DisplayName, principal.DisplayName);
                    result.Add(principal.SamAccountName);
                }
                return result;
            }
        }
    }

此代码正确找到用户主体，但在调用 GetGroups 时失败，并出现 PrincipalOperationException: Unknown error (0x80005000)。

根异常：

   at System.DirectoryServices.AccountManagement.ADStoreCtx.GetGroupsMemberOf(Principal foreignPrincipal, StoreCtx foreignContext)
   at System.DirectoryServices.AccountManagement.Principal.GetGroupsHelper(PrincipalContext contextToQuery)
   at System.DirectoryServices.AccountManagement.Principal.GetGroups(PrincipalContext contextToQuery)
   at [line of the GetGroup call]

内部异常（COMException）：

   at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
   at System.DirectoryServices.DirectoryEntry.Bind()
   at System.DirectoryServices.DirectoryEntry.get_AdsObject()
   at System.DirectoryServices.PropertyValueCollection.PopulateList()
   at System.DirectoryServices.PropertyValueCollection..ctor(DirectoryEntry entry, String propertyName)
   at System.DirectoryServices.PropertyCollection.get_Item(String propertyName)
   at System.DirectoryServices.AccountManagement.ADUtils.RetriveWkDn(DirectoryEntry deBase, String defaultNamingContext, String serverN

Another report with this problem.

有什么线索吗？

Answer 1

添加 Environment.UserDomainName 作为 PrincipalContext 的名称参数有助于：

using (var context = new PrincipalContext(ContextType.Domain, Environment.UserDomainName))

我仍然不知道为什么 PrincipalContext(ContextType.Domain) 仅适用于查找 UserPrincipal 而不是用户组。 COM 错误消息“未知错误”不是很有帮助，只有 ContextType 的 PrincipalContext 构造函数重载在 MSDN 中几乎没有记录。正如 Harvey Kwok 所指出的，这听起来像是 .NET 框架的问题。

Answer 2

正如问题 cmets 中所述，调用GetGroups 时可能发生此特定错误的另一个原因是由于a documented bug in .NET and .NET Core。尝试为 AD 可分辨名称中带有斜杠 ('/') 的用户主体获取组时会发生这种情况。

至少在修复错误之前，解决方法是编写自己的GetGroups 方法。这是一个只返回组名（还包括分发列表）的工作示例：

public static List<string> GetGroups(UserPrincipal user)
{
    List<string> groupNames = new List<string>();

    using (DirectoryEntry directoryEntryUser = (DirectoryEntry)user.GetUnderlyingObject())
    {
        object[] groups = GetAdPropertyValueObjectArray(directoryEntryUser, "memberOf");
        const int prefixLength = 3;
        const string prefix = "CN=";  // CN = Common Name

        if (groups != null)
        {
            foreach (string group in groups)
            {
                if (group.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
                {
                    int commaIndex = group.IndexOf(",", prefixLength);
                    string groupName;

                    if (commaIndex >= 0)
                        groupName = group.Substring(prefixLength, commaIndex - prefixLength);
                    else
                        groupName = group.Substring(prefixLength);

                    if (groupName.Length > 0)
                        groupNames.Add(groupName);
                }
            }
        }
    }

    return groupNames;
}

private static object[] GetAdPropertyValueObjectArray(DirectoryEntry userAccount, string adPropertyKey)
{
    object[] result = null;
    PropertyValueCollection property = userAccount.Properties[adPropertyKey];

    if (property != null)
    {
        object propertyValue = property.Value;

        if (propertyValue != null)
        {
            if (propertyValue is string)
            {
                result = new object[1];
                result[0] = propertyValue;
            }
            else
            {
                result = (object[])propertyValue;
            }
        }
    }

    return result;
}