var queryTyped =
from c in contacts.OfType<CustomerContact>()
select c;

var queryFiltered =
from c in contacts
where c is CustomerContact
select c;

foreach( var row in queryTyped ) {
	Console.WriteLine( row.Company );
}

// Potebujeme explicitn petypovn, abychom mohli pistupovat ke lenm // CustomerContact.
foreach( CustomerContact row in queryFiltered ) {
	Console.WriteLine( row.Company );
}
