设计模式学习--观察者模式

  1 using System;
  2 using System.Collections;
  3 using System.Collections.Generic;
  4 using System.Linq;
  5 using System.Text;
  6 using System.Threading.Tasks;
  7 
  8 namespace ObserverPattern
  9 {
 10 
 11 //创建发送者的接口
 12     public interface IObserver
 13     {
 14         void update(float temp, float humidity, float pressure);
 15     }
 16 //主题接口，供注册和解除监听
 17     public interface ISubject
 18     {
 19         void registerObserver(IObserver o);
 20         void removeObserver(IObserver o);
 21         void notifyObserver();
 22     }
 23         //显示接口
 24     public interface IDisplayElement
 25     {
 26         void display();
 27     }
 28 
 29 //源，实现监听者的添加删除以及发送消息
 30     public class WeatherData : ISubject
 31     {
 32         public ArrayList observers;
 33         public float temperature;
 34         public float humidity;
 35         public float pressure;
 36 
 37 
 38         public WeatherData()
 39         {
 40             observers = new ArrayList();
 41         }
 42 
 43 
 44         public void registerObserver(IObserver o)
 45         {
 46             observers.Add(o);
 47         }
 48 
 49         public void removeObserver(IObserver o)
 50         {
 51             observers.Remove(o);
 52         }
 53 //给每个监听者发送消息
 54         public void notifyObserver()
 55         {
 56             for (int i = 0; i < observers.Count; i++)
 57             {
 58                 (observers[i] as IObserver).update(temperature, humidity, pressure);
 59             }
 60         }
 61 
 62 //触发消息
 63         public void measurementsChanged()
 64         {
 65             notifyObserver();
 66         }
 67 //设置消息值
 68         public void setMeasurements(float temperature, float humidity, float pressure)
 69         {
 70             this.temperature = temperature;
 71             this.humidity = humidity;
 72             this.pressure = pressure;
 73 
 74             measurementsChanged();
 75         }
 76 
 77     }
 78 
 79 //监听者之一
 80     public class CurrentConditionsDisplay : IObserver, IDisplayElement
 81     {
 82 
 83 
 84 
 85         public float temperature;
 86         public float humidity;
 87         public float pressure;
 88         private ISubject WeatherData;
 89         public CurrentConditionsDisplay(ISubject WeatherData)
 90         {
 91             this.WeatherData = WeatherData;
 92             WeatherData.registerObserver(this);//把自己注册进去监听
 93         }
 94 
 95 //weather会调用这个方法
 96         public void update(float temp, float humidity, float pressure)
 97         {
 98             this.temperature = temp;
 99             this.humidity = humidity;
100             this.pressure = pressure;
101             display();
102         }
103 //显示
104         public void display()
105         {
106             Console.WriteLine("Current conditions:" + temperature + "F degrees and " + humidity + "humidity");
107         }
108 
109 
110     }
111 }