A data structure(tree) with multiple classes

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I ran to an issue, I have a task with categories and items, I need to make a menu tree list, it can be N deep, parent can have many children as he wants:

Menu tree looks like this:

- Category (6)
    - Category (3)
      - Item (€0.50)
      - Category (2)
        - Item (€1.10)
        - Item (€6.25)
      -Category (1)
        - Item (€3.33)
    - Category (2)
      - Item (€1.10)
      - Item (€9.99)
    - Category (0)
- Category (2)
    - Category (1)
        - Item (€0.50)
    -Category (1)
        - Item (€0.60)

The item can have properties - name, active, price. The category can have - name, active.

So could I have any suggestions what kind of tree should I be using ? Do I have to create 2 tables for this tree, because in my opinion category should not know anything about a price, also maybe make Item open to new changes, for example adding new fields.

What I have tried:

I only did only a research and I thought I could find an opinion who had maybe did something similar or have any clue what kind of data structure should I use.

Posted 24-Feb-18 2:42am

Dntdothis

Updated 24-Feb-18 5:19am

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BillWoodruff 24-Feb-18 9:54am

Is this a WinForms project ? When you say "menu," do you mean there's some visual UI that's part of this ?

Have you written any code ?

"create 2 tables for this tree" are you talking about a database table, here ?

Dntdothis 24-Feb-18 9:59am

Yeah, 2 tables, well I did not wrote any code, since I want to have a clear vision how to do it from architecture side.

BillWoodruff 24-Feb-18 10:29am

Is it the case that an Item Node will always be a leaf node: i.e., it will never contain other nodes ? That's yhe structure your code shows now.

Dntdothis 24-Feb-18 10:30am

Yeah, it is like a product with price, so it would not contain childs

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BillWoodruff · Accepted Answer · 2018-02-24T05:12:00

Knowing your tree's item nodes are always leaf nodes of a specific type makes your task a bit simpler. I'm going to post a sketch of a structure that will implement a tree of this type which I know works. I say "sketch" because my goal is to assist you in developing your programming skills ... so, I am leaving key pieces of the code out for you to work out.

using System.Collections.Generic;

namespace YourNameSpace
{
{
    public interface IMenu
    {
        string Name { get; set; }
        bool IsActive { get; set; }
    }

    public class MenuTree
    {
        public MenuTree(string name)
        {
            Name = name;
            Categories = new List<Category>();
        }

        string Name { get; set; }

        List<Category> Categories { get; set; }

        public Category AddCategory(Category cat)
        {
            // what happens here ?
        }
    }

    public class Category : IMenu
    {
        public Category(string name, bool isActive = true)
        {
            Name = name;
            IsActive = isActive;
            MenuItems = new List<MenuTreeItem>();
            Categories = new List<Category>();
        }

        public string Name { get; set; }
        public bool IsActive { get; set; }

        public List<Category> Categories { get; set; }
        public List<MenuTreeItem> MenuItems { get; set; }

        public Category AddCategory(Category cat)
        {
             // what happens here ?
        }

        public void AddMenuItem(MenuTreeItem itm)
        {
             // what happens here ?
        }
    }

    public class MenuTreeItem : IMenu
    {
        public MenuTreeItem(string name, double price,  bool isActive = true)
        {
            // what happens here ?
        }

        // see note #1
        public Category MItemCategory { get; set; }

        // what other Fields or Properties must be defined ?
    }
}

If this code were complete, it could be used like this:

MenuTree mTree = new MenuTree("TestMenuTree");

int id = 1;

for (int i = 0; i < 5; i++)
{
    Category cat1 = mTree.AddCategory(new Category($"Cat_{i}"));

    for (int j = 0; j < 3; j++)
    {
        cat1.AddMenuItem(new MenuTreeItem($"mi_{id++}", (j * 11.11) + 22));
    }

    Category cat2 = cat1.AddCategory(new Category($"Cat_{i}_A"));

    for (int j = 0; j < 3; j++)
    {
        cat2.AddMenuItem(new MenuTreeItem($"mi_{id++}", (j * 23.45) + 56.45));
    }
}

note #1: Should the reference to the Item's 'Category be passed in the Item's constructor rather than be set by the 'AddMenuItem method of the Category ?