items in Listview and Treeview

HI

is there a way to add an item to listview and treeview without
first dimming an object of that type's item ?

when i add an item, one of the parameters is a "key" which is unique and help me to identify that item later on
but it doesnt work, i have to dim an item type
then add the item to the list/tree view and on that item add the subitems, or child items...

isnt there a way to add an item with a unique key so later on i can do whatever i want with it just by using that key?