C#设计模式之Observer观察者模式解决牛顿童鞋成绩问题示例

所属分类：软件编程 / C#教程阅读数： 116

收藏 0赞 0分享

本文实例讲述了C#设计模式之Observer观察者模式解决牛顿童鞋成绩问题。分享给大家供大家参考，具体如下：

一.理论定义

观察者模式描述了一种一对多的关系。当某一对象的状态发生改变时，其他对象会得到改变的通知。并作出相应的反应。

二.应用举例

需求描述：牛顿同学的期末考试成绩(Score)出来了，各科老师都想知道自己的学生成绩情况！
语文老师(TeacherChinese)只关心牛顿的语文(Chinese)成绩.
英语老师(TeacherEnglish)只关心牛顿的英语(English)成绩.
数学老师(TeacherMathematics)只关心牛顿的数学(Mathematics)成绩.
班主任想关心(TeacherTeacherHead) 牛顿的各科成绩和总成绩(TotalScore).
成绩出来后，各科老师都得到通知(Notify).

三.具体编码

1.添加学生信息类，里面只有一个Name属性。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 /// <summary>
 /// 学生信息类
 /// </summary>
 public class Student
 {
  /// <summary>
  /// 姓名
  /// </summary>
  public string Name { get; set; }
 }
}

2.成绩单(Score)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 public delegate void NotifyEventHandler(Score score);
 public class Score
 {
  public Score() { }
  //事件声明
  public NotifyEventHandler NotifyEvent=null;
  /// <summary>
  /// 调用入口
  /// </summary>
  public void Notify() {
   OnNotifyChange();
  }
  /// <summary>
  ///通知事件
  /// </summary>
  private void OnNotifyChange() {
   if (NotifyEvent != null) {
    NotifyEvent(this);
   }
  }
  /// <summary>
  /// 数学成绩
  /// </summary>
  public float Mathematics { get; set; }
  /// <summary>
  /// 英语成绩
  /// </summary>
  public float English { get; set; }
  /// <summary>
  /// 语文成绩
  /// </summary>
  public float Chinese { get; set; }
  /// <summary>
  /// 三科总成绩
  /// </summary>
  public float TotalScore {
   get {
    return Mathematics+English+Chinese;
   }
  }
  /// <summary>
  /// 学生基本信息
  /// </summary>
  public Student student { get; set; }
 }
}

3.语文老师

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 /// <summary>
 /// 语文老师
 /// </summary>
 public class TeacherChinese
 {
  public void Receive(Score score) {
   Console.WriteLine("我是语文老师，我只关心"+score.student.Name+"的语文成绩:"+score.Chinese+"分");
  }
 }
}

4.英语老师

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 /// <summary>
 /// 英语老师
 /// </summary>
 public class TeacherEnglish
 {
  public void Receive(Score score) {
   Console.WriteLine("我是英语老师，我只关心" + score.student.Name + "的英语成绩:" + score.English + "分");
  }
 }
}

5.数学老师

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 /// <summary>
 /// 数学老师
 /// </summary>
 public class TeacherMathematics
 {
  public void Receive(Score score) {
   Console.WriteLine("我是数学老师，我只关心" + score.student.Name + "的数学成绩:" + score.Mathematics + "分");
  }
 }
}

6.班主任

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Com.Design.Gof.Observer
{
 /// <summary>
 /// 班主任
 /// </summary>
 public class TeacherTeacherHead
 {
  public void Receive(Score score) {
   string name=score.student.Name;
   Console.WriteLine("我是班主任，我要关心 " + name + " 的各科成绩和总成绩");
   Console.WriteLine(name + "的 语文 成绩: " + score.Chinese + " 分");
   Console.WriteLine(name + "的 英语 成绩: " + score.English + " 分");
   Console.WriteLine(name + "的 数学 成绩: " + score.Mathematics + " 分");
   Console.WriteLine(name + "的 总 成绩: " + score.TotalScore + " 分");
  }
 }
}

7.下面是主函数调用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Com.Design.Gof.Observer;
namespace Com.Design.Gof.Test
{
 class Program
 {
  static void Main(string[] args)
  {
   #region Observer
   /*牛顿同学的成绩单*/
   Score score = new Score {
    Chinese = 60,
    Mathematics = 100,
    English = 90,
    student = new Student { Name = "牛顿" }
   };
   TeacherChinese teacherChinese = new TeacherChinese(); //语文老师
   TeacherEnglish teacherEnglish = new TeacherEnglish();//英语老师
   TeacherMathematics teacherMathematics = new TeacherMathematics();//数学老师
   TeacherTeacherHead teacherTeacherHead = new TeacherTeacherHead();//班主任
   //牛顿成绩单出来了，老师都想知道这个结果。
   score.NotifyEvent += new NotifyEventHandler(teacherChinese.Receive);
   score.NotifyEvent += new NotifyEventHandler(teacherEnglish.Receive);
   score.NotifyEvent += new NotifyEventHandler(teacherMathematics.Receive);
   score.NotifyEvent += new NotifyEventHandler(teacherTeacherHead.Receive);
   //向 各 学科 老师发送 有针对性的，感兴趣的 成绩
   score.Notify();
   #endregion
   Console.ReadKey();
  }
 }
}

8.运行结果