Treeview hell

Question

Hi, I'm trying to use a treeview control in this little app and it's giving me a headache. Basically I want to programatically add a child to a node, but only the last child in the nodecollection for the control. Imagine the structure is like this: item1 -item2 --item3 ---item4 I want the user to be able to add a child, but only to, in this case, item4. There's an abundance of examples on how to add a node using selectedNode.nodes.add, but that requires user interaction. Hopefully I explained myself alright.