1  public interface Isub
2     {
3         void addobser(Iobse obe);
4         void removeobser(Iobse ove);
5         void notify();
6     }

1 public interface Iobse
2     {
3         void update(float times);
4     }

 1 public class clock : Isub
 2     {
 3         private float times;
 4         List<Iobse> obse=new List<Iobse>() ;
 5
 6         public float Times
 7         {
 8             get
 9             {
10                 return times;
11             }
12
13             set
14             {
15                 times = value;
16             }
17         }
18
19         public void addobser(Iobse obe)
20         {
21             obse.Add(obe);
22         }
23
24         public void notify()
25         {
26             for(int i = 0; i < obse.Count(); i++)
27             {
28                 Iobse Iose = (Iobse)obse[i];
29                 Iose.update(Times);
30             }
31         }
32
33         public void removeobser(Iobse ove)
34         {
35             obse.Remove(ove);
36         }
37     }

 1 public class A : Iobse
 2     {
 3         private float times;
 4         private clock c2 = new clock();
 5         public A(clock c2)
 6         {
 7             this.c2 = c2;
 8             c2.addobser(this);
 9         }
10         public void update(float times)
11         {
12             this.times = times;
13             if (times > 9 * 60)                    //这里是我们对所关心的数据times所作出的一个反映——打印出一条信息
14             {
15                 MessageBox.Show("已经9点，可以起床了");
16             }
17         }
18     }

 1  public class B : Iobse
 2     {
 3         private float times;
 4         private clock c1 = new clock();
 5         public B(clock c1)
 6         {
 7             this.c1 = c1;
 8             c1.addobser(this);
 9         }
10
11
12
13         public void update(float times)
14         {
15             this.times = times;
16             if (times > 9 * 60 + 30)
17             {
18                 MessageBox.Show("已经超过9点半了，上班要迟到了");
19             }
20         }
21     }

1  private void button_Click(object sender, RoutedEventArgs e)
2         {
3             clock c1 = new clock();
4             c1.Times = 9 * 60 + 2;
5             A a = new A(c1);
6             B b = new B(c1)；
7             c1.notify();
8         }