Project here http://www.nwoods.com/forum/uploads/HuffmanTree.zip
VS2010, GoDiagram 4.2, .NET 4.0
2 buttons in the button bar: first one adds the sample graph above. Second one just does a “layout”
the nodes aren’t sorted by TreeLayout (by default) so adding them to the document in the order you want them is important.
I’ve left traversing your structure and doing the “AddNode” calls as a “to do” for you.