我可以从 DirectorySearcher 中获取 1000 多条记录吗？

Question

I just noticed that the return list for results is limited to 1000. I have more than 1000 groups in my domain (HUGE domain). How can I get more than 1000 records? Can I start at a later record? Can I cut it up into multiple searches?

Here is my query:

DirectoryEntry dirEnt = new DirectoryEntry("LDAP://dhuba1kwtn004");
string[] loadProps = new string[] { "cn", "samaccountname", "name", "distinguishedname" };
DirectorySearcher srch = new DirectorySearcher(dirEnt, "(objectClass=Group)", loadProps);
var results = srch.FindAll();

I have tried to set srch.SizeLimit = 2000; , but that doesn't seem to work. Any ideas?

Answer 1

You need to set DirectorySearcher.PageSize to a non-zero value to get all results.

BTW you should also dispose DirectorySearcher when you're finished with it

using(var srch = new DirectorySearcher(dirEnt, "(objectClass=Group)", loadProps))
{
    srch.PageSize = 1000;
    var results = srch.FindAll();
}

The API documentation isn't very clear, but essentially:

• when you do a paged search, the SizeLimit is ignored, and all matching results are returned as you iterate through the results returned by FindAll. Results will be retrieved from the server a page at a time. I chose the value of 1000 above, but you can use a smaller value if preferred. The tradeoff is: using a small PageSize will return each page of results faster, but will require more frequent calls to the server when iterating over a large number of results.

• by default the search isn't paged (PageSize = 0). In this case up to SizeLimit results is returned.

As Biri pointed out, it's important to dispose the SearchResultCollection returned by FindAll, otherwise you may have a memory leak as described in the Remarks section of the MSDN documentation for DirectorySearcher.FindAll .

One way to help avoid this in .NET 2.0 or later is to write a wrapper method that automatically disposes the SearchResultCollection. This might look something like the following (or could be an extension method in .NET 3.5):

public IEnumerable<SearchResult> SafeFindAll(DirectorySearcher searcher)
{
    using(SearchResultCollection results = searcher.FindAll())
    {
        foreach (SearchResult result in results)
        {
            yield return result;        
        } 
    } // SearchResultCollection will be disposed here
}

You could then use this as follows:

using(var srch = new DirectorySearcher(dirEnt, "(objectClass=Group)", loadProps))
{
    srch.PageSize = 1000;
    var results = SafeFindAll(srch);
}

Answer 2

I tried to use given solution to achieve pagination but it doesnt work. I set pageSize = 100; and i get all the items through searchResult.

dirSearcher = new DirectorySearcher(direntry); dirSearcher.Filter = ("(|(objectClass=volume). (objectClass=user)(objectClass=printQueue)(objectClass=computer). (objectClass=organizationalUnit)(objectClass=Group))");

            dirSearcher.PageSize = 100;
            dirSearcher.SearchScope = System.DirectoryServices.SearchScope.Subtree;
            dirSearcher.ServerTimeLimit = new TimeSpan(1000);

            //dirSearcher.VirtualListView = new DirectoryVirtualListView(0, 100, 1);


            using (SearchResultCollection results = dirSearcher.FindAll())
            {
                foreach (SearchResult result in results)
                {
                    DirectoryEntry ent = result.GetDirectoryEntry();
                    ADItem ProviderItem = Context.ConvertToItem(ent, true);

                    if (ProviderItem != null)
                    {
                        ProviderItem.IsPartialData = true;
                        ProviderItems.Add(ProviderItem);
                    }
                }

            }
        }