BizDraw framework for .NET

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Runtime.Serialization;
using System.Collections;
using BizDraw.Core;
namespace BizDraw.Objects
{
    [System.Runtime.InteropServices.ComVisible(true)]
    [Serializable()]
    public class GraphicsList : List<DrawObject>
    {
        public GraphicsList()
        {
        
        }
        #region Collection Methods
        public new void Add(DrawObject item)
        {
            PrepareObject(item);
            base.Insert (0, item);
         
        }
        internal void PrepareObject(DrawObject item)
        {
            item.Parent = this;
            item.SelectChanged += new EventHandler(item_SelectChanged);
        }
        void item_SelectChanged(object sender, EventArgs e)
        {
            OnSelectedObjectChanged(sender, e);
        }
        public new void Insert(int index, DrawObject item)
        {
            PrepareObject(item);
            base.Insert(index, item);
        }
        #endregion
        #region Non Collection Properties
        [NonSerialized()]
        internal Document parentDocument; 
        /// <summary>
        /// SelectedCount and GetSelectedObject allow to read
        /// selected objects in the loop
        /// </summary>
        public int SelectionCount
        {
            get
            {
                int n = 0;

                foreach (DrawObject o in this)
                {
                    if (o.Selected)
                        n++;
                }

                return n;
            }
        }

        #endregion
        #region Non Collection Methods
        public void Draw(Graphics g)
        {
            int n = this.Count;
            DrawObject o;

            // Enumerate list in reverse order
            // to get first object on the top
            for (int i = n - 1; i >= 0; i--)
            {
                o = this[i];

                o.Draw(g);

                if (o.Selected == true)
                {
                    o.DrawTracker(g);
                }
            }
        }
        public DrawObject GetSelectedObject(int index)
        {
            int n = -1;

            foreach (DrawObject o in this)
            {
                if (o.Selected)
                {
                    n++;

                    if (n == index)
                        return o;
                }
            }

            return null;
        }
        public void SelectInRectangle(Rectangle rectangle)
        {
            UnselectAll();

            foreach (DrawObject o in this)
            {
                if (o.IntersectsWith(rectangle))
                    o.SetSelectedState(true);
            }

        }

        public void UnselectAll()
        {
            foreach (DrawObject o in this)
            {
                o.SetSelectedState(false);
            }
        }

        public void SelectAll()
        {
            foreach (DrawObject o in this)
            {
                o.SetSelectedState(true);
            }
        }

        internal void SetDirty()
        {
        }
        #endregion
        #region events
        public event EventHandler SelectedObjectChanged;
        protected void OnSelectedObjectChanged(object sender, EventArgs e)
        {
            if (SelectedObjectChanged != null)
                SelectedObjectChanged(sender, e);
        }
        #endregion
    }
}