Why should you care?

ShopNest category menus nest categories and leaf products under one render API.

See it live — copy this example

Paste into a C# console or class library project and run dotnet run.

public interface IMenuNode { void Print(int indent = 0); }
public sealed class MenuItem : IMenuNode
{
    private readonly string _name;
    public MenuItem(string name) => _name = name;
    public void Print(int indent = 0) => Console.WriteLine($"{new string(' ', indent)}- {_name}");
}
public sealed class MenuGroup : IMenuNode
{
    private readonly string _name;
    private readonly List<IMenuNode> _children = new();
    public MenuGroup(string name) => _name = name;
    public void Add(IMenuNode n) => _children.Add(n);
    public void Print(int indent = 0)
    {
        Console.WriteLine($"{new string(' ', indent)}[{_name}]");
        foreach (var c in _children) c.Print(indent + 2);
    }
}

var root = new MenuGroup("Catalog");
root.Add(new MenuItem("Phones"));
var audio = new MenuGroup("Audio");
audio.Add(new MenuItem("Headphones"));
root.Add(audio);
root.Print();

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• MenuGroup and MenuItem both build IMenuNode.
• Print recurses.
• Callers do not care if a node is leaf or branch.

Practice next

1. Print the sample tree.
2. Add another nested group.
3. Count leaves with a recursive helper.
4. Add Remove on MenuGroup.
5. Print SKU counts per group.

Remember

Uniform tree interface. Leaves and composites. Recursive operations.

ShopNest nested categories

Admin renders category trees with one Print/Walk API.

Outcome: UI code stays simple for deep menus.