By using the NodeDataBound
event you can easily get reference to the level of the nodes in the following way:
var nodeLevel= e.DropDownTreeNode.Level;
Indeed, currently there is no way to get reference to the tree in the dropdown but with the upcoming Service Pack1 this week, we will introduce both client-side and server-side properties and methods that will allow access to the tree.
I would also recommend that you take a look at this help article as I believe it would be helpful in your scenario - How to Pre-Select a Node Based on Text or Value.
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