Question

I have an object of a custom type I’ve made (Menu) which can contain child elements of the same type, which naturally can contain child elements and so on.

I wish to generate menus and submenus out of these objects, but I’m wondering how I can traverse them recursively so that I don’t have to hard code all my loops. I am a stranger to recursion, is anyone able to shed some light on how to traverse the Menu object and all the underlying objects?

Example code:

public class Menu {
    public int MenuID { get; set; }
    public int Name { get; set; }
    public Menu[] _ChildMenus { get; set; }
}

Answer 1

Here is one option:

private void TraverseMenu(Menu menu)
{
    Output(string.Format("Now reading menu #{0}, named {1}", menu.MenuID, menu.Name));
    if (menu._ChildMenus != null)
    {
        foreach (Menu child in menu._ChildMenus)
        {
            TraverseMenu(child);
        }
    }
}

If you need to know how “deep” each menu is nested you can add a level parameter:

private void TraverseMenu(Menu menu, int level)
{
    Output(string.Format("Now reading menu #{0}, named {1} in level {2}", menu.MenuID, menu.Name, level));
    if (menu._ChildMenus != null)
    {
        foreach (Menu child in menu._ChildMenus)
        {
            TraverseMenu(child, level + 1);
        }
    }
}

private void TraverseMenu(Menu menu)
{
    TraverseMenu(menu, 0);
}