Find custom controls in aspx page any depth

PageHelper.cs

/// <summary>
/// Extension method for the "Page" class
/// </summary>
public static class PageHelper
{
    /// <summary>
    /// Find control in the page
    /// </summary>
    /// <typeparam name="T">return control type(eg. TextBox)</typeparam>
    /// <param name="page">Actual Page</param>
    /// <param name="id">control id</param>
    /// <returns></returns>
    public static T GetControl<T>(this Page page, string id)
            where T : Control
    {
        return (FindControlRecursive(page, id) as T);
    }

    /// <summary>
    /// Find control recursive
    /// </summary>
    /// <param name="root">root contol(eg. Page)</param>
    /// <param name="id">control id</param>
    /// <returns></returns>
    private static Control FindControlRecursive(Control root, string id)
    {
        if (root.ID == id)
        {
            return root;
        }
        foreach (Control ctl in root.Controls)
        {
            var foundCtl = FindControlRecursive(ctl, id);
            if (foundCtl != null)
            {
                return foundCtl;
            }
        }
        return null;
    }
}