using System;
using System.Collections.Generic;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;

public class FibonacciControl : CompositeControl
{
    public FibonacciControl()
    {
        // ....
    }

    protected override void CreateChildControls()
    {
        base.CreateChildControls();

        ListView view = new ListView();

        view.LayoutTemplate = new LayoutTemplate();
        view.ItemTemplate = new ItemTemplate();

        view.DataSource = FibonacciSequence();
        view.DataBind();

        this.Controls.Add(view);
    }

    private IEnumerable<int> FibonacciSequence()
    {

        int i1 = 0;
        int i2 = 1;

        for (int i = 0; i < Iterations; i++)
        {
            yield return i1 + i2;
            int temp = i1 + i2;
            i1 = i2;
            i2 = temp;
        }
        yield break;
    }

    public int Iterations { get; set; }

    private class LayoutTemplate : ITemplate
    {

        public void InstantiateIn(Control container)
        {
            var ol = new HtmlGenericControl("ol");
            var li = new HtmlGenericControl("li") { ID = "itemPlaceholder" };
            ol.Controls.Add(li);

            container.Controls.Add(ol);
        }
    }

    private class ItemTemplate : ITemplate
    {
        public void InstantiateIn(Control container)
        {
            var li = new HtmlGenericControl("li");

            li.DataBinding += DataBinding;
            container.Controls.Add(li);
        }

        public void DataBinding(object sender, EventArgs e)
        {
            var container = (HtmlGenericControl)sender;
            var dataItem = ((ListViewDataItem)container.NamingContainer).DataItem;

            container.Controls.Add(new Literal() { Text = dataItem.ToString() });
        }
    }
}