Tim Van Wassenhove

Because i always seem to forget about the syntax of LDAP Search Filters (RFC 2254: The String Representation of LDAP Search Filters and Creating a Query Filter) i’m going to post a basic demo of DirectorySearcher that returns the members that are part of a given AD group:

private static void Main(string[] args)
{
 foreach (string member in FindUsernames("?CWBE-PS-.NetDev"))
 {
  Console.WriteLine(member);
 }

 Console.Write("{0}Press any key to continue...", Environment.NewLine);
 Console.ReadKey();
}

private static IEnumerable<string> FindUsernames(string groupname)
{
 string filter = "(&(&(objectCategory=Group)(objectClass=Group))(name={0}))";
 filter = string.Format(filter, groupname);

 DirectoryEntry directoryEntry = new DirectoryEntry();
 DirectorySearcher searcher = new DirectorySearcher(directoryEntry);
 searcher.SearchScope = SearchScope.Subtree;
 searcher.Filter = filter;

 DirectoryEntry groupEntry = searcher.FindOne().GetDirectoryEntry();
 PropertyValueCollection members = (PropertyValueCollection)groupEntry.Properties["member"];
 return ConvertAll<object, string>((object[])members.Value);
}

private static IEnumerable<to> ConvertAll<from, To>(IEnumerable<from> elements)
{
 Type toType = typeof(To);

 foreach (From element in elements)
 {
  yield return (To)Convert.ChangeType(element, toType);
 }
}