"获取分页 DirectorySearcher 的搜索结果总数"

Question

I am using a DirectorySearch<\/code> to search for objects in an Active Directory. I set the VirtualListView<\/code> property to return just a few values:

using System;
using System.DirectoryServices;

namespace Testbed
{
    internal class Testbed
    {
        private static void Main()
        {
            DoSearch();
            Console.ReadKey();
        }

        private static void DoSearch()
        {
            var entry = new DirectoryEntry("LDAP://server/DC=mydomain,DC=com", @"USERNAME", "PASSWORD");
            var searcher = new DirectorySearcher(entry)
            {
                PageSize = 0,
                SearchScope = SearchScope.Subtree,
                Filter = "(Description=J_*)",
                Sort = new SortOption("Description", SortDirection.Ascending),
                VirtualListView = new DirectoryVirtualListView(0, 9, 1)
            };

            SearchResultCollection results = searcher.FindAll();
            foreach (SearchResult result in results)
            {
                Console.WriteLine(result.Properties["Description"][0]);
            }
            Console.WriteLine("Found: " + results.Count);
        }
    }
}

Answer 1

There is an ApproximateTotal property inside DirectoryVirtualListView class. You can use it, but remember you should access it after the foreach block in your code. Just change this line:

Console.WriteLine("Found: " + results.Count);

to this one:

Console.WriteLine("Found: " + searcher.VirtualListView.ApproximateTotal);

All done!

Answer 2

I've ran into a situation where VirtualListView.ApproximateTotal returns zero. I've only encountered this running in netcoreapp3.1 however.

    using var searcher = new DirectorySearcher(rootEntry)
    {
        SearchScope = SearchScope.Subtree,
        Filter = query,
        Sort = new SortOption(criteria.Sort, sortDirection),
        VirtualListView = new DirectoryVirtualListView(0, pageSize - 1, end),
        PageSize = 0
    };
    var searchResults = searcher.FindAll();

    foreach (SearchResult searchResult in searchResults)
    {
        //do something with entity here ...
    }


    //hack to properly get totals
    var virtualListView = searchResults.GetType().GetProperty("VLVResponse", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic)?.GetValue(searchResults) as DirectoryVirtualListView;
    var count = virtualListView?.ApproximateTotal;

    //Instead of simply 
    //var count = searchResults.Count;