programming the active directory - active-directory

Question

I've got an asp application running but i want to search the Active Directory.
i am using vb (visual web developer 2008)
how do i search the active directory for a given user?
ie: user enters login name in text box, clicks submit. active directory is searched on-click for this user. when found user information is displayed .
Thanks

Answer 1

What version of the .NET framework can you use? Searching and looking up stuff in AD has become extremely easy in .NET 3.5 - see this great MSDN article by Ethan Wilanski and Joe Kaplan on using the security principals API for that.
If you're not on .NET 3.5 yet, you'll have to use the DirectorySearcher class and set up the search filters as you need. Getting the LDAP filter right is probably the biggest obstacle.
Robbie Allen also has two great intro article on System.DirectoryServices programming:
- Part 1
- Part 2
There are some really good resources at http://www.directoryprogramming.net (Joe Kaplan's site - he's a Microsoft Active Directory MVP), and Richard Mueller has some great reference excel sheets on what properties are available for each of the ADSI providers, and what they mean, and how their LDAP name is - see http://www.rlmueller.net.
Marc
EDIT: Ok- here's the .NET 2.0 / 3.0 approach:
// set the search root - the AD container to search from
DirectoryEntry searchRoot = new DirectoryEntry("LDAP://dc=yourdomain,dc=com");
// create directory searcher
DirectorySearcher ds = new DirectorySearcher(searchRoot);
ds.SearchScope = SearchScope.Subtree;
// set the properties to load in the search results
// the fewer you load, the better your performance
ds.PropertiesToLoad.Add("cn");
ds.PropertiesToLoad.Add("sn");
ds.PropertiesToLoad.Add("givenName");
ds.PropertiesToLoad.Add("mail");
// set the filter - here I'm using objectCategory since this attribute is
// single-valued and indexed --> much better than objectClass in performance
// the "anr" is the "ambiguous name resolution" property which basically
// searches for all normally interesting name properties
ds.Filter = "(&(objectCategory=person)(anr=user-name-here))";
// get the result collection
SearchResultCollection src = ds.FindAll();
// iterate over the results
foreach (SearchResult sr in src)
{
// do whatever you need to do with the search result
// I'm extracting the properties I specified in the PropertiesToLoad
// mind you - a property might not be set in AD and thus would
// be NULL here (e.g. not included in the Properties collection)
// also, all result properties are really multi-valued, so you need
// to do this trickery to get the first of the values returned
string surname = string.Empty;
if (sr.Properties.Contains("sn"))
{
surname = sr.Properties["sn"][0].ToString();
}
string givenName = string.Empty;
if (sr.Properties.Contains("givenName"))
{
givenName = sr.Properties["givenName"][0].ToString();
}
string email = string.Empty;
if (sr.Properties.Contains("mail"))
{
email = sr.Properties["mail"][0].ToString();
}
Console.WriteLine("Name: {0} {1} / Mail: {2}", givenName, surname, email);
}
Hope this helps!
Marc