Ok...
Here's what I did...
FlyTreeNodeCollection col = ftvTEST.Nodes[0].ChildNodes.FindByValue(\"17\");
col[0].ChildNodes.Add( new FlyTreeNode( \"test\" ) );
Worked.
If you are pulling back a set of departments whose department number will be 17, will there be more than one?
If so, I don't know how to tell the difference.
You may want to add the new node to each of the children.
FlyTreeNodeCollection col = ftvTEST.Nodes[0].ChildNodes.FindByValue(\"17\");
FlyTreeNode newNode = new FlyTreeNode();
newNode.Text = \"Shirt\"; // add an item.
newNode.Value = \"0009893829382\"; // add sku or upc or whatever
foreach( FlyTreeNode node in col )
{
node.ChildNodes.Add( newNode );
}
But if you're sure you'll only be returning one node with the 'FindByValue' method, you can use the first example.