Validating user credentials against active directory

I have following code that validates a given user credentails against a
active directory. The login part works but I can not search fails to return
the record. Does any one have any idea what is wrong?

public void Login(string user, string pwd, string domain)
{
string path = "<<my ldap path>>";

DirectoryEntry domainEntry = new DirectoryEntry(path);
domainEntry.Username = domain + @"\" + user;
domainEntry.Password = pwd;

domainEntry.AuthenticationType = AuthenticationTypes.Secure;

string searchFilter = "sAMAccountName=" + user;

DirectorySearcher searcher = new DirectorySearcher(domainEntry,
searchFilter);

searcher.SearchScope = SearchScope.Subtree;

//The following line throws exception if supplied user
credentails are not valid
SearchResult result = searcher.FindOne();
Console.WriteLine("Login succeeded.");

if (result == null)
{
Console.WriteLine("Search for user failed.");
Console.WriteLine();
}
else
{
Console.WriteLine("Search for user succeeded.");
}
}

Thanks.
Raghu/..

Raghu
Tue Apr 18 10:41:51 CDT 2006

Found the answer. Needed to use following filter.

string searchFilter = String.Format("(&(objectClass=user)(sAMAccountName=
{0}))", user);

"Raghu" <RaghuNoSpam> wrote in message
news:%23W3yk1kYGHA.2376@TK2MSFTNGP03.phx.gbl...
>I have following code that validates a given user credentails against a
>active directory. The login part works but I can not search fails to return
>the record. Does any one have any idea what is wrong?
>
> public void Login(string user, string pwd, string domain)
> {
> string path = "<<my ldap path>>";
>
> DirectoryEntry domainEntry = new DirectoryEntry(path);
> domainEntry.Username = domain + @"\" + user;
> domainEntry.Password = pwd;
>
> domainEntry.AuthenticationType = AuthenticationTypes.Secure;
>
> string searchFilter = "sAMAccountName=" + user;
>
> DirectorySearcher searcher = new DirectorySearcher(domainEntry,
> searchFilter);
>
> searcher.SearchScope = SearchScope.Subtree;
>
> //The following line throws exception if supplied user
> credentails are not valid
> SearchResult result = searcher.FindOne();
> Console.WriteLine("Login succeeded.");
>
> if (result == null)
> {
> Console.WriteLine("Search for user failed.");
> Console.WriteLine();
> }
> else
> {
> Console.WriteLine("Search for user succeeded.");
> }
> }
>
> Thanks.
> Raghu/..
>