CSharp:Observer Pattern

 

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/// <summary> /// Summary description for Observer. /// Observer Pattern 观察者 ///20220918 /// geovindu,Geovin Du,涂聚文 /// </summary> public interface Observer {     void sendNotify(string message); }

　　

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/// <summary> /// Summary description for Subject. /// Observer Pattern 观察者 ///20220918 /// geovindu,Geovin Du,涂聚文 /// </summary> public interface Subject {     void registerInterest(Observer obs); }

　　

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/// <summary>  /// Observer Pattern 观察者  ///20220918  /// geovindu,Geovin Du,涂聚文  /// </summary>  public partial class ListObsForm : Form, Observer  {        /// <summary>      ///      /// </summary>      public ListObsForm(Subject subj)      {          InitializeComponent();          init(subj);      }        /// <summary>      ///      /// </summary>      /// <param name="subj"></param>      public void init(Subject subj)      {          subj.registerInterest(this);      }      /// <summary>      ///      /// </summary>      /// <param name="message"></param>      public void sendNotify(string message)      {          lsColors.Items.Add(message);      }        /// <summary>      ///      /// </summary>      /// <param name="sender"></param>      /// <param name="e"></param>      private void ListObsForm_Load(object sender, EventArgs e)      {        }  }

　　

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/// <summary>  /// Observer Pattern 观察者  ///20220918  /// geovindu,Geovin Du,涂聚文  /// </summary>  public partial class ColObserverForm : Form, Observer  {      private Brush bBrush;      // private System.Windows.Forms.PictureBox pic;      private Font fnt;      private Hashtable colors;      private string colName;        /// <summary>      ///      /// </summary>      /// <param name="subj"></param>      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 = "";      }      /// <summary>      ///      /// </summary>      /// <param name="message"></param>      public void sendNotify(string message)      {          colName = message;          message = message.ToLower();          Color col = (Color)colors[message];          pic.BackColor = col;      }      /// <summary>      ///      /// </summary>      /// <param name="sender"></param>      /// <param name="e"></param>      private void paintHandler(object sender, PaintEventArgs e)      {          Graphics g = e.Graphics;          g.DrawString(colName, fnt, bBrush, 20, 40);      }        /// <summary>      ///      /// </summary>      public ColObserverForm(Subject subj)      {          InitializeComponent();          init(subj);      }      /// <summary>      ///      /// </summary>      /// <param name="sender"></param>      /// <param name="e"></param>      private void ColObserverForm_Load(object sender, EventArgs e)      {        }  }

　　

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/// <summary>  /// Observer Pattern 观察者  ///20220918  /// geovindu,Geovin Du,涂聚文  /// </summary>  public partial class ObserverPatternForm : Form, Subject  {      private ArrayList observers;        /// <summary>      ///      /// </summary>      private void init()      {          EventHandler evh = new EventHandler(opButton_Click);          opRed.Click += evh;          opBlue.Click += evh;          opGreen.Click += evh;          observers = new ArrayList();          ListObsForm lobs = new ListObsForm(this);          lobs.Show();          ColObserverForm colObs = new ColObserverForm(this);          colObs.Show();      }      /// <summary>      ///      /// </summary>      /// <param name="obs"></param>      public void registerInterest(Observer obs)      {          observers.Add(obs);      }      /// <summary>      ///      /// </summary>      public ObserverPatternForm()      {          InitializeComponent();          init();      }      /// <summary>      ///      /// </summary>      /// <param name="sender"></param>      /// <param name="e"></param>      private void ObserverPatternForm_Load(object sender, EventArgs e)      {        }        /// <summary>      ///      /// </summary>      /// <param name="sender"></param>      /// <param name="e"></param>      private void opButton_Click(object sender, System.EventArgs e)      {          RadioButton but = (RadioButton)sender;          for (int i = 0; i < observers.Count; i++)          {              Observer obs = (Observer)observers[i];              obs.sendNotify(but.Text);          }      }  }

　　

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