WPF get children from layout by name

Hi guys i have really special problem.... I need return child from layout by name... But method findName works only on XAML. But i create layout with label programmatically and i neeed search Label by name from layout. Thanks for some help.

Grid g = (Grid) tasks.SelectedItem;

Label b = (Label)g.FindName("idLabel");

Console.WriteLine(b.Content); //b is null

 

And guys i havent variable i know only name..