Adyt Adyt - 10 months ago 51
C# Question

Quick way to retrieve user information Active Directory

How to query user information from Active Directory? I have code that works, but it's really slow. I'm using C#.
This is the code I currently use:

static void Main(string[] args)
SearchResultCollection sResults = null;

//modify this line to include your domain name
string path = "LDAP://EXTECH";
//init a directory entry
DirectoryEntry dEntry = new DirectoryEntry(path);

//init a directory searcher
DirectorySearcher dSearcher = new DirectorySearcher(dEntry);

//This line applies a filter to the search specifying a username to search for
//modify this line to specify a user name. if you want to search for all
//users who start with k - set SearchString to "k"
dSearcher.Filter = "(&(objectClass=user))";

//perform search on active directory
sResults = dSearcher.FindAll();

//loop through results of search
foreach (SearchResult searchResult in sResults)
if (searchResult.Properties["CN"][0].ToString() == "Adit")
////loop through the ad properties
//foreach (string propertyKey in

//pull the collection of objects with this key name
ResultPropertyValueCollection valueCollection =

foreach (Object propertyValue in valueCollection)

//loop through the values that have a specific name
//an example of a property that would have multiple
//collections for the same name would be memberof
//Console.WriteLine("Property Name: " + valueCollection..ToString());
Console.WriteLine("Property Value: " + (string)propertyValue.ToString());

Console.WriteLine(" ");
catch (InvalidOperationException iOe)
catch (NotSupportedException nSe)

// dispose of objects used
if (sResults != null)


What would faster code look like to get user information from AD?

Answer Source

The reason why your code is slow is that your LDAP query retrieves every single user object in your domain even though you're only interested in one user with a common name of "Adit":

dSearcher.Filter = "(&(objectClass=user))";

So to optimize, you need to narrow your LDAP query to just the user you are interested in. Try something like:

dSearcher.Filter = "(&(objectClass=user)(cn=Adit))";

In addition, don't forget to dispose these objects when done:

  • DirectoryEntry dEntry
  • DirectorySearcher dSearcher