Populate a DropDown with Windows Authenticated users?

Question

I have come up empty-handed in my search for this. Anyone have an answer? Using MVC3/C#. Thanks.

Answer 1

One way to do this is to use System.DirectoryServices.DirectorySearcher to ask for the list of users from active directory.

Update

Here is the class that we use; you can call the FetchContacts static method to retrieve the users:

using System;
using System.Collections.Generic;
using System.DirectoryServices;

public class ActiveDirectorySystem
{
    private const string PROPERTY_DISPLAY_NAME = "displayName";

    private static DirectorySearcher Initialize()
    {
        // Exceptions are handled by the caller

        // Obtain the domain root entry
        using (DirectoryEntry theRootEntry = new DirectoryEntry("LDAP://RootDSE"))
        {
            object theNamingContext = null;
            string sNamingContext = null;

            // Verify that we retrieved it correctly and raise an error if we did not
            if (theRootEntry == null)
            {
                throw new Exception("A directory services entry for the LDAP RootDSE could not be created.");
            }

            // Get the root naming context
            theNamingContext = theRootEntry.Properties["rootDomainNamingContext"].Value;
            // Verify that we retrieved it correctly and raise an error if we did not
            if ((theNamingContext == null) || (theNamingContext.ToString().Length == 0))
            {
                throw new Exception("The root domain naming context property could not be retrieved from the LDAP directory services");
            }
            else
            {
                sNamingContext = theNamingContext.ToString();
            }

            // And create a new directory entry for the root naming context
            using (DirectoryEntry theEntry = new DirectoryEntry("LDAP://" + sNamingContext))
            {
                // Verify that we retrieved it correctly and raise an error if we did not
                if (theEntry == null)
                {
                    throw new Exception("A directory entry object could not be created for LDAP://" + sNamingContext);
                }

                // Now we configure what we are looking for from Active Directory
                DirectorySearcher oSearcher = null;

                // Start with a new searcher for the root domain
                oSearcher = new DirectorySearcher(theEntry);
                // Verify that we retrieved it correctly and raise an error if we did not
                if (oSearcher == null)
                {
                    throw new Exception("A directory searcher object could not be created for LDAP://" + sNamingContext);
                }

                // And the properties we want to retrieve
                oSearcher.PropertiesToLoad.Add(PROPERTY_DISPLAY_NAME);

                return oSearcher;
            }
        }
    }

    /// <summary>
    /// This method retrieves the set of users from active directory that meet the criteria specified in filter.
    /// </summary>
    /// <param name="sFilter"></param>
    /// <returns></returns>
    /// <remarks></remarks>
    public static List<string> FetchContacts(string sFilter = "")
    {
        // Exceptions are handled by the caller

        using (DirectorySearcher oSearcher = Initialize())
        {
            if (oSearcher != null)
            {
                List<string> cNames = new List<string>();

                // Specify what we are looking for, which is the account name of the specified user without any domain information
                oSearcher.Filter = string.Format("(&(objectCategory=person)(objectClass=user){0})", sFilter);

                // get all of the matching records
                using (SearchResultCollection cResults = oSearcher.FindAll())
                {
                    if (cResults != null)
                    {
                        foreach (SearchResult theCurrentResult in cResults)
                        {
                            System.DirectoryServices.ResultPropertyCollection oProperties = null;

                            oProperties = theCurrentResult.Properties;
                            // First, verify that at least the display name is contained in the result
                            if (oProperties.Contains(PROPERTY_DISPLAY_NAME) && oProperties[PROPERTY_DISPLAY_NAME].Count > 0)
                            {
                                cNames.Add(oProperties[PROPERTY_DISPLAY_NAME][0].ToString());
                            }
                        }
                    }
                }

                return cNames;
            }
        }

        return null;
    }
}