My program is attempting to draw [grammars](http://en.wikipedia.org/wiki/Formal_grammar) in C# & WPF. I have:

1 DataStructure project which describes a tree structure of how it should be visualised. Each node in the tree relates to a symbol in the grammar. Nodes at the top define the rule for that nonterminal symbol.

1 Drawer project which describes the user controls in WPF.

I need to reference drawer in my datastructure as when i traverse the tree, I call *DataStructure.draw();* on each node. I also need to reference the datastructure in my drawer project so I can respond to a user clicking on my GUI, it will update the data structure.

This creates a circular depedency, I have tried to use a controller class but I have no idea :/