I have this simple code I call

  foreach (XamTreeItem item in treeCatType.XamTreeItems)
            {
                item.IsExpanded = false;
            }

but everytime I call it the XamTreeItems.Count=0 ?????

it's Itemsource is a binding to collection of 2 tiered objects.

Everything else seems to be working but this code never does.

Any Ideas why?