Get user details from AD username

DirectoryEntry de = new DirectoryEntry("LDAP://server.com"));
DirectorySearcher ds = new DirectorySearcher(de);
ds.Filter = "(sAMAccountName=" + user + ")";
SearchResult sr = ds.FindOne();
string LastName = sr.Properties["sn"][0].ToString();
string FirstName = sr.Properties["givenName"][0].ToString();