using System;using System.Collections; //要用ArrayList要引用这个class CourseScore {  //普通的属性用法    private string name;    private int courseID;    private int score;    public CourseScore(string name, int courseID, int score) {        this.name = name;        this.courseID = courseID;        this.score = score;    }    public string Name {        get { return name; }        set { name = value; }    }    public int CourseID {        get { return courseID; }        set { courseID = value; }    }    public int Score {        get { return score; }        set { score = value; }    }}class CourseScoreIndexer {  //构造器    private ArrayList arrCourseScore;    public CourseScoreIndexer() {        arrCourseScore = new ArrayList();    }    public int this[string name, int courseID] {  //构造器只能用this        get {            foreach (CourseScore cs in arrCourseScore) {                if (cs.Name == name && cs.CourseID == courseID) {                    return cs.Score;                }            }            return -1;        }        set {            arrCourseScore.Add(new CourseScore(name, courseID, value));  //hashtable用.Add        }    }    public ArrayList this[string name] {        get {            ArrayList tempArr = new ArrayList();            foreach (CourseScore cs in arrCourseScore) {                if (cs.Name == name) {                    tempArr.Add(cs);                }            }            return tempArr;        }    }}class Test {    static void Main() {        CourseScoreIndexer csi = new CourseScoreIndexer();        csi["张三", 1] = 90;        csi["张三", 2] = 80;        csi["李四", 1] = 70;        Console.WriteLine("张三的第2门课程分数为：" + csi["张三", 2]);        ArrayList tempArr = csi["张三"];        foreach (CourseScore cs in tempArr) {            Console.WriteLine("姓名：" + cs.Name + "  课程编号：" + cs.CourseID + "  分数：" + cs.Score);        }        Console.ReadKey();    }}