从Active directory中的特定组和OU中检索用户

我想从Active Directory中的特定OU检索给定组中的所有用户。我的代码抛出了一个异常

操作被中止，因为超出了客户端超时限制

我在

处得到这个异常

foreach (SearchResultEntry entry in searchResponse.Entries)

我的组名是Arya, OU名是TestOU

但是当我把过滤器写成

string searchFilter = "(&(objectCategory=user)" 

它工作并返回所有OU的用户，我认为这是我不想要的。

bool bMoreData = false;
DirectoryEntry rootDSE = new DirectoryEntry("LDAP://" + domain);
string[] attributes = { "samaccountname", "displayname", "name", "initials" };
System.Net.NetworkCredential credential = new System.Net.NetworkCredential(admin, password, "IP address");
LdapDirectoryIdentifier directoryIdentifier = new LdapDirectoryIdentifier("ip address"); //389 (unsecured LDAP)
LdapConnection connection = new LdapConnection(directoryIdentifier, credential);
connection.Bind();
string searchFilter = "(&(objectCategory=user)(memberOf=cn=Arya,ou=TestOU,dc=Maintenance,dc=org))";
SearchRequest request = new SearchRequest("DC=Maintenance,DC=org", searchFilter, System.DirectoryServices.Protocols.SearchScope.Base, attributes);
// getCookie();
DirSyncRequestControl dirSyncRC = new DirSyncRequestControl(cookie, System.DirectoryServices.Protocols.DirectorySynchronizationOptions.IncrementalValues, Int32.MaxValue);
request.Controls.Add(dirSyncRC);
SearchResponse searchResponse = (SearchResponse)connection.SendRequest(request);
foreach (SearchResultEntry entry in searchResponse.Entries)// Exception thrown here
{
    Console.WriteLine("{0}:{1}",
    searchResponse.Entries.IndexOf(entry),
    entry.DistinguishedName);
}
foreach (DirectoryControl control in searchResponse.Controls)
{
    if (control is DirSyncResponseControl)
    {
        DirSyncResponseControl dsrc = control as DirSyncResponseControl;
        cookie = dsrc.Cookie;
        bMoreData = dsrc.MoreData;
        break;
    }
}

DirSyncRequestControl dirSyncRC = new DirSyncRequestControl(cookie, System.DirectoryServices.Protocols.DirectorySynchronizationOptions.IncrementalValues, Int32.MaxValue);

DirSyncRequestControl dirSyncRC = new DirSyncRequestControl(cookie, System.DirectoryServices.Protocols.DirectorySynchronizationOptions.ObjectSecurity, Int32.MaxValue);

// create your domain context - bind to the OU you're interested in
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain, null, "OU=TestOU"))
{
   // define a "query-by-example" principal - here, we search for any GroupPrincipal 
   GroupPrincipal group = ctx.FindByIdentity("Arya");
   // if group is found - enumerate its members
   if(group != null) 
   {
       foreach(var found in group.GetMembers())
       {
            // 
       }
   }
}