Tree structure with subclassed nodes, how to apply operation on a subset of children

Question

I have a tree structure

A -> B -> D -> Y
  -> C -> X
       -> X

I want to do an operation on all objects of class X, or all the children objects of class D (for example). I want to call start this operation from any node in the tree (ie recursively).

For e.g,

A.SetupDecorators();

(although I'm open to suggestions)

All classes inherit from a superclass.

Is there a nice OO solution for this without using reflection?

C# is preferred.

Answer 1

Try Visitor Design Pattern and the example code in C#