The AnywherePlaceHolder. Part 3. The AnywhereValidationSummaryPlaceHolder

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

namespace DeKale.WebControls
{
	/// <summary>
	/// Builds up a tree of <see cref="System.Web.UI.Control"/> objects and
	/// enables specific searches through the tree.
	/// </summary>
	class ControlTree : IEnumerable<Control>
	{
		private ControlCollection _collection;
		private List<ControlTree> _childNodes = new List<ControlTree>();

		/// <summary>Constructor</summary>
		/// <param name="collection">The <see cref="System.Web.UI.ControlCollection"/> object</param>
		public ControlTree(ControlCollection collection)
		{
			this._collection = collection;

			foreach (Control control in collection)
			{
				if (control != null && control.Controls != null) 
					this._childNodes.Add(new ControlTree(control.Controls));
			}
		}

		/// <summary>
		/// Adds all the <see cref="Control"/> objects of itself and it's children to the
		/// <paramref name="controlList"/>.
		/// </summary>
		/// <param name="controlList">A given <see cref="IList"/> in which all controls are added.</param>
		protected void AppendList(IList<Control> controlList)
		{
			foreach (Control item in this._collection) controlList.Add(item);
			foreach (ControlTree node in this._childNodes) node.AppendList(controlList);
		}

		#region IEnumerable<Control> Members

		/// <summary>
		/// Returns an <see cref="IEnumerator"/> that iterates through the <see cref="ControlTree"/>.
		/// </summary>
		/// <returns>The <see cref="IEnumerator"/></returns>
		public IEnumerator<Control> GetEnumerator()
		{
			List<Control> list = new List<Control>();
			this.AppendList(list);

			foreach (Control item in list) yield return item;
		}

		#endregion

		#region IEnumerable Members

		/// <summary>
		/// Returns an <see cref="IEnumerator"/> that iterates through the <see cref="ControlTree"/>.
		/// </summary>
		/// <returns>The <see cref="IEnumerator"/></returns>
		IEnumerator IEnumerable.GetEnumerator()
		{
			List<Control> list = new List<Control>();
			this.AppendList(list);

			return list.GetEnumerator();
		}

		#endregion
	}

}