Fast way to get a list of group members in Active Directory with C#

Question

In a web app, we\'re looking to display a list of sam accounts for users that are a member of a certain group. Groups could have 500 or more members in many cases and we need t

Answer 1

Have you tried an LDAP query? The bottom of the page has an example in C# for enumerating through a group to get members. MSDN BOL

using System;
using System.DirectoryServices;

namespace ADAM_Examples
{
class EnumMembers
{
    /// 

    /// Enumerate AD LDS groups and group members.
    /// 
    [STAThread]
    static void Main()
    {
        DirectoryEntry objADAM;                   // Binding object.
        DirectoryEntry objGroupEntry;             // Group Results.
        DirectorySearcher objSearchADAM;          // Search object.
        SearchResultCollection objSearchResults;  // Results collection.
        string strPath;                           // Binding path.

        // Construct the binding string.
        strPath = "LDAP://localhost:389/OU=TestOU,O=Fabrikam,C=US";
        Console.WriteLine("Bind to: {0}", strPath);
        Console.WriteLine("Enum:    Groups and members.");

        // Get the AD LDS object.
        try
        {
            objADAM = new DirectoryEntry(strPath);
            objADAM.RefreshCache();
        }
        catch (Exception e)
        {
            Console.WriteLine("Error:   Bind failed.");
            Console.WriteLine("         {0}", e.Message);
            return;
        }

        // Get search object, specify filter and scope,
        // perform search.
        try
        {
            objSearchADAM = new DirectorySearcher(objADAM);
            objSearchADAM.Filter = "(&(objectClass=group))";
            objSearchADAM.SearchScope = SearchScope.Subtree;
            objSearchResults = objSearchADAM.FindAll();
        }
        catch (Exception e)
        {
            Console.WriteLine("Error:   Search failed.");
            Console.WriteLine("         {0}", e.Message);
            return;
        }

        // Enumerate groups and members.
        try
        {
            if (objSearchResults.Count != 0)
            {
                foreach(SearchResult objResult in objSearchResults)
                {
                    objGroupEntry = objResult.GetDirectoryEntry();
                    Console.WriteLine("Group    {0}",
                        objGroupEntry.Name);
                    foreach(object objMember
                        in objGroupEntry.Properties["member"])
                    {
                        Console.WriteLine(" Member: {0}",
                            objMember.ToString());
                    }
                }
            }
            else
            {
                Console.WriteLine("Results: No groups found.");
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Error:   Enumerate failed.");
            Console.WriteLine("         {0}", e.Message);
            return;
        }

        Console.WriteLine("Success: Enumeration complete.");
        return;
    }
}

}