HandymanVisitorExample.cs

using System.Collections.Generic;

public class House
{
    public List<Room> Rooms;

    public void AcceptVisitor(IVisitor visitor)
    {
        //The handyman will perform checks on this house 
        //(e.g. check the outside walls)
        //The house does not care what the handyman does. 
        visitor.VisitHouse(this);

        //Next, the handyman will go from room to room
        foreach (var room in Rooms)
        {
            room.AcceptVisitor(visitor);
        }
    }
}

public class Room
{
    public void AcceptVisitor(IVisitor visitor)
    {
        //The handyman performs his checks and fixes on this room. 
        //The room does not care what the handyman does.
        visitor.VisitRoom(this);
    }
}

//Visitors

public interface IVisitor
{
    void VisitHouse(House house);

    void VisitRoom(Room room);
}

public class Plumber : IVisitor
{
    public void VisitHouse(House house)
    {
        CheckOutsidePipes(house);
    }

    public void VisitRoom(Room room)
    {
        //The plumber checks and fixes leaky pipes (if any) in that room
        CheckPipes(room);
    }

    private void CheckPipes(Room room)
    {
        //Implementation omitted for the simplicity of the example
    }

    private void CheckOutsidePipes(House house)
    {
        //Implementation omitted for the simplicity of the example
    }
}

public class CableTechnician : IVisitor
{
    public void VisitHouse(House house)
    {
        CheckOutsideCableWirings(house);
    }

    public void VisitRoom(Room room)
    {
        CheckTV(room);
        CheckModem(room);
    }

    private void CheckModem(Room room)
    {
        //Implementation omitted for the simplicity of the example
    }

    private void CheckTV(Room room)
    {
        //Implementation omitted for the simplicity of the example
    }

    private void CheckOutsideCableWirings(House house)
    {
        //Implementation omitted for the simplicity of the example
    }
}