Codeusing System;using System.Collections.Generic;using System.Text;

namespace Example04{    #region 基类，抽象类    public abstract class BaseClass    {        //抽象属性，同时具有get和set访问器表示继承类必须将该属性实现为可读写        public abstract String Attribute        {            get;            set;        }

        //抽象方法，传入一个字符串参数无返回值        public abstract void Function(String value);

        //抽象事件，类型为系统预定义的代理(delegate)：EventHandler        public abstract event EventHandler Event;

        //抽象索引指示器，只具有get访问器表示继承类必须将该索引指示器实现为只读        public abstract Char this[int Index]        {            get;        }    }    #endregion

    #region 继承类    public class DeriveClass : BaseClass    {        private String attribute;

        public override String Attribute        {            get            {                return attribute;            }            set            {                attribute = value;            }        }        public override void Function(String value)        {            attribute = value;            if (Event != null)            {                Event(this, new EventArgs());            }        }        public override event EventHandler Event;        public override Char this[int Index]        {            get            {                return attribute[Index];            }        }    }    #endregion

    class Program    {        static void OnFunction(object sender, EventArgs e)        {            for (int i = 0; i < ((DeriveClass)sender).Attribute.Length; i++)            {                Console.WriteLine(((DeriveClass)sender)[i]);            }        }        static void Main(string[] args)        {            DeriveClass tmpObj = new DeriveClass();

            tmpObj.Attribute = "1234567";            Console.WriteLine(tmpObj.Attribute);

            //将静态函数OnFunction与tmpObj对象的Event事件进行关联            tmpObj.Event += new EventHandler(OnFunction);

            tmpObj.Function("7654321");

            Console.ReadLine();        }    }}