Question

I have a class hierarchy as such:

        +-- VirtualNode         | INode --+                  +-- SiteNode         |                  |         +-- AbstractNode --+                            |                            +-- SiteSubNode 

And a corresponding NodeCollection class that is build on INode. In order to display a NodeCollection I need to know the final type of each member. So I need a function like this

foreach (INode n in myNodeCollection) {     switch(n.GetType())     {         case(typeof(SiteNode)):         // Display n as SiteNode     } } 

Now, this is really not an object oriented way of doing it. Are there any patterns or recommended ways of doing the same thing, in your opinion?

EDIT
I already thought of adding a Display or Render method to the INode interface. That has the side effect of coupling the view to the model, which I would really like to avoid.

Answer 1

What you’re after is the visitor pattern, I think.