观察者模式,越详细越好.200分送上.大家看分的份上啊该如何处理

//Subject.cs
using System;

namespace Observer
{
    /// <summary>
    /// Summary description for Subject.
    /// </summary>
    public interface Subject     {
         void registerInterest(Observer obs);
    }
}

//ListObs.cs
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;

namespace Observer
{
    /// <summary>
    /// Summary description for ListObs.
    /// </summary>
    public class ListObs : System.Windows.Forms.Form, Observer
    {
        private System.Windows.Forms.ListBox lsColors;
        /// <summary>
        /// Adds text of color to list box
        /// </summary>
        private System.ComponentModel.Container components = null;

        public ListObs(Subject subj)         {
            InitializeComponent();
            init(subj);
        }
        //------
        public void init(Subject subj) {
            subj.registerInterest (this);
        }
        //------
        public void sendNotify(string message){
            lsColors.Items.Add(message);
        }
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if(components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.lsColors = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            // 
            // lsColors
            // 
            this.lsColors.Location = new System.Drawing.Point(16, 16);
            this.lsColors.Name = "lsColors";
            this.lsColors.Size = new System.Drawing.Size(216, 173);
            this.lsColors.TabIndex = 0;
            // 
            // ListObs
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(264, 213);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.lsColors});
            this.Name = "ListObs";
            this.Text = "List observer";
            this.ResumeLayout(false);

        }
        #endregion
    }
}


//Observer.cs
using System;

namespace Observer
{
    /// <summary>
    /// Summary description for Observer.
    /// </summary>
    public interface Observer     {
        void sendNotify(string message);
    }
}


//ColObserver.cs
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;

namespace Observer
{
    /// <summary>
    /// Summary description for ColObserver.
    /// </summary>
    public class ColObserver : System.Windows.Forms.Form, Observer     {
        private System.ComponentModel.Container components = null;
        private Brush bBrush;
        private System.Windows.Forms.PictureBox pic;
        private Font fnt;
        private Hashtable colors;
        private string colName;
        //-----
        public ColObserver(Subject subj)         {
            InitializeComponent();
            init(subj);
        }
        //-----
        private void init(Subject subj) {
            subj.registerInterest (this);
            fnt = new Font("arial", 18, FontStyle.Bold);
            bBrush = new SolidBrush(Color.Black);
            pic.Paint+= new PaintEventHandler (paintHandler);
            colors = new Hashtable ();
            colors.Add("red", Color.Red );
            colors.Add ("blue", Color.Blue );
            colors.Add ("green", Color.Green );
            colName = "";
        }
        //-----
        public void sendNotify(string message) {
            colName = message;
            message = message.ToLower ();
            Color col = (Color)colors[message];
            pic.BackColor = col;
        }
        //-----
        private void paintHandler(object sender, PaintEventArgs e) {
             Graphics g = e.Graphics ;
             g.DrawString(colName, fnt, bBrush, 20, 40);
        }
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if(components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.pic = new System.Windows.Forms.PictureBox();
            this.SuspendLayout();
            // 
            // pic
            // 
            this.pic.BackColor = System.Drawing.SystemColors.ActiveCaptionText;
            this.pic.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.pic.Location = new System.Drawing.Point(24, 24);
            this.pic.Name = "pic";
            this.pic.Size = new System.Drawing.Size(184, 152);
            this.pic.TabIndex = 0;
            this.pic.TabStop = false;
            // 
            // ColObserver
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(248, 213);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.pic});
            this.Name = "ColObserver";
            this.Text = "Color observer";
            this.ResumeLayout(false);

        }
        #endregion
    }
}