Command is an abstract class which defines the interface expected by the undo manager for undoing or redoing actions. All actions that can be carried out by NetDiagram in response to users' input or method calls are implemented in Command subclasses. For a list of Command-derived classes see Actions and Commands.
The Execute, Undo or Redo methods are defined as abstract and must be implemented by derived classes. You must not call these methods directly - use the Undo or Redo methods of the UndoManager instead.