用PrincipalSearcher分页

Question

我使用PrincipalSearcher时需要分页。我尝试使用基础DirectorySearcher的DirectorySearcher属性，但没有结果。

Samplecode：

using System;
using System.DirectoryServices;
using System.DirectoryServices.AccountManagement;
using System.Linq;
namespace Testbed
{
    internal class Testbed
    {
        private static void Main(string[] args)
        {
            Works();
            Fails();
            Console.ReadKey();
        }

        private static void Works()
        {
            var entry = new DirectoryEntry("LDAP://server/DC=example,DC=com", @"USERNAME", "PASSWORD");
            var searcher = new DirectorySearcher(entry);

            searcher.SearchScope = SearchScope.Subtree;
            searcher.Filter = "(cn=*)";
            // sort is needed, otherwise DVLV will not work?
            searcher.Sort = new SortOption("cn", SortDirection.Ascending);

            searcher.VirtualListView = new DirectoryVirtualListView(5, 10, 5);
            SearchResultCollection result = searcher.FindAll();
            Console.WriteLine("Works: " + result.Count);
        }

        private static void Fails()
        {
            var context = new PrincipalContext(ContextType.Domain, "server", "DC=example,DC=com",
                ContextOptions.Negotiate,
                @"USERNAME", "PASSWORD");

            var user = new UserPrincipal(context)
            {
                DisplayName = null,
            };

            var searcher = new PrincipalSearcher(user);
            ((DirectorySearcher) searcher.GetUnderlyingSearcher()).Sort = new SortOption("cn", SortDirection.Ascending);
            ((DirectorySearcher) searcher.GetUnderlyingSearcher()).VirtualListView = new DirectoryVirtualListView(0, 2, 2);
            PrincipalSearchResult<Principal> result = searcher.FindAll();

            Console.WriteLine("Fails: " + result.Count());
        }
    }
}

当我直接使用DirectorySearcher (方法：Works())时，一切都很好，但是对于PrincipalSearcher (方法：Fails())，我得到了以下异常(对德文表示抱歉)：

Ausnahmefehler: System.Runtime.InteropServices.COMException: Die angeforderte kritische Erweiterung wird vom Server nicht unterstützt.

   bei System.DirectoryServices.SearchResultCollection.ResultsEnumerator.MoveNext()
   bei System.DirectoryServices.AccountManagement.ADEntriesSet.MoveNext()
   bei System.DirectoryServices.AccountManagement.FindResultEnumerator`1.MoveNext()
   bei System.DirectoryServices.AccountManagement.FindResultEnumerator`1.System.Collections.IEnumerator.MoveNext()
   bei System.Linq.Enumerable.Count[TSource](IEnumerable`1 source)

有什么解决办法吗？PrincipalSearcher甚至有可能做到这一点吗？

Answer 1

PrincipalSearcher的默认页面大小设置为265。尝试将其设置为0，如下所示：

((DirectorySearcher) searcher.GetUnderlyingSearcher()).PageSize = 0;

这将启用分页。DirectorySearcher的默认PageSize为0，这就是直接使用它时工作的原因。