Hi,
you are in fact a little unprecise, but I'll try:
Assume you have:
List<int> numbers = new List<int>(new int[] { 1, 2, 3, 4, 5, 6, 7 });
var odds =
from number in numbers
where (number % 2) == 1
select number;
Whenever you add another number (let's say: 13) a subsequent call to odds will automatically reflect the changes (the new result is: 1,3,5,7,13). If that is, what you asked, then there is no option and there is no need for.
If you're thinking of something like:
List<int> oddnumbers = odds.ToList();
numbers.Add(13);
then 'oddnumbers' is a completly new object that has nothing to do with/no link to 'numbers' or 'odds'. So it does not contain the '13'. The same applies when you're using the ToList()-method in the query definition statement (or 'ToArray()' or 'let').
If you need to reflect changes in 'numbers', you could use an ObservableCollection instead of a List and requery upon the CollectionChanged-event. But be sure to keep an eye on your memory if you're dealing with large resultsets.
Cheers