Is there a way to build string showing a TreeView hierarchical struct?

I have a treeview and it's used for managing the folders/programs in a systray program launcher I made.  I wanted to add a way to move multiple programs to other parent folders easily.  I figured no big deal, I'll make the TreeView allow multiple selection, that's not an issue right?  Welllll apparently it is.  So I figured OK, I'll build a little popup window that asks you to select the parent for the items then have a listbox that shows all the available nodes and you select what you want.  Easy peasy.

 

However...  I can't figure out the right way to build my listbox items.  Say I have a treeview with these nodes: 

I want my resultant listbox to have:

I see the TreeNodes have a Parent property so I figured I'd make a method I can call that calls itself and builds the list.  To make a long story short; it was a hot mess, lol.  Did not work well.  I just can't wrap my head around the correct process/flow.

 

Each TreeNode's Tag is a wrapper "Node" which has a property to determine if it's a folder or a program. I figure I can check that as I iterate the nodes and check if ((Node)treeNode.Tag).NodeClass == NodeClasses.Folder then I know I don't have to add it to the listbox.

 

Can someone assist?  Thanks! 

 

PS on a tangent here, but out of curiosity...  that NodeClasses enum, my Java teacher said enum properties should be UPPERCASE.  I see in most code examples in C# they are PascalCase.  Is that the accepted standard for C#?  I really don't like all caps so I avoided it.  Just curious if that's against naming conventions or not.