public abstract void Visit(ConcreteElementA me);
public VisitorPattern()
{
var concreteElementB = new ConcreteElementB();
concreteElementB.Accept(new ConcreteVisitor());
var concreteElementA = new ConcreteElementA();
concreteElementA.Accept(new ConcreteVisitor());
}
public override void Visit(ConcreteElementA me)
{
Console.WriteLine("ConcreteElementA");
}