给Asp.Net初学者的关于继承和多态性的例子

本人学Asp.Net不久,用的是C#写代码,在学习C#中发现很多初学者对继承和多态性不是特别的了解,因此作了这个例子,希望对您有所帮助,例子很简单

页面文件TestProfileClass2.aspx

<%@ Page Language="C#" ContentType="text/html" ResponseEncoding="gb2312" src="profile2.cs" %>

<%@ Import Namespace="shai" %>

<html>

<head>

<style>

div{font:Arial, Helvetica, sans-serif;

background-color:#cccccc;

border-color:black;

border-width:1;

border-style:solid;

padding:10,10,10,10;

}

</style>

<script language="c#" runat="server">

public void Page_Load(Object sender,EventArgs e)

{

  Profile profile = new Profile();

  message.InnerHtml += "<u>Profile Class</u><br>";

  message.InnerHtml += "Firstname:"+profile.getFirstname()+"<br>";

  message.InnerHtml += "Lastname:"+profile.getLastname()+"<br>";

  message.InnerHtml += "Phone:"+profile.getPhonenumber()+"<br><br>";

  profile.save();

  ExtendedProfile extendedprofile = new ExtendedProfile();

  message.InnerHtml += "<u>ExtendedProfile Class</u></br>";

  message.InnerHtml += "Firstname:"+profile.getFirstname()+"<br>";

  message.InnerHtml += "Lastname:"+profile.getLastname()+"<br>";

  message.InnerHtml += "Phone:"+extendedprofile.getPhonenumber()+"<br>";

  message.InnerHtml += "Address1:"+extendedprofile.getAddress1()+"<br>";

  message.InnerHtml += "Address2:"+extendedprofile.getAddress2()+"<br>";

  message.InnerHtml += "City:"+extendedprofile.getCity()+"<br>";

  message.InnerHtml += "State:"+extendedprofile.getState()+"<br>";

  message.InnerHtml += "Postal:"+extendedprofile.getPostal()+"<br>";

  message.InnerHtml += "Description:"+extendedprofile.getDescription()+"<br>";

  extendedprofile.save();

}

</script>

<meta http-equiv="Content-Type" content="text/html; charset=gb2312">

<title></title>

</head>

<body style="font:Arial, Helvetica, sans-serif ">

<b><h3>简单的继承/多态例子</h3></b><br><br>

object output:<br>

<br>

<div id="message" runat="server" />

</body>

</html>

类定义文件profile2.cs

using System;

using System.IO;

using System.Xml;

namespace shai     //名称空间shai

{

  interface ISaveData    //定义一个接口ISaveData,他作为Profile的基类被继承,由于其有多态性的特点,可以被

  {                                //不同类调用其中的方法,并修改

    void save();

  }

  public class Profile:ISaveData     //定义类Profile

  {

    protected string _firstname;       //里面包含三个属性,分别为_firstname、_lastname、phonenumber

    protected string _lastname;

    protected string _phonenumber;

 public Profile()                            //为属性定义其中的初始值

 {

   _firstname = "Saidy";

   _lastname = "Chen";

   _phonenumber = "(010)88716990";

 }

 public string getPhonenumber()           //Profile类中的方法getPhonenumber()

 {

   return _phonenumber;

 }

 public virtual void setPhonenumber(string phonenumber)

 {

   _phonenumber = phonenumber;

 }

 public string getFirstname()                 //Profile类中的方法getFirstname()

 {

   return _firstname;

 }

 public void setFirstname(string firstname)

 {

   _firstname = firstname;

 }

 public string getLastname()                  //Profile类中的方法getLastname()

 {

   return _lastname;

 }

 public void setLastname(string lastname)

 {

   _lastname = lastname;

 }

 public virtual void save()            //调用ISaveData接口的save()方法

 {

   //保存数据为Text格式

   FileStream fs = new FileStream("D:\\myweb2\\profile2.txt",FileMode.Create,FileAccess.Write);

   StreamWriter sw = new StreamWriter(fs);

   sw.WriteLine("Firstname:"+_firstname.ToString());

   sw.WriteLine("Lastname:"+_lastname.ToString());

   sw.WriteLine("Phone:"+_phonenumber.ToString());

   sw.Flush();

   sw.Close();

   fs.Close();

  }

}

  public class ExtendedProfile:Profile        建立Profile子类ExtendedProfile,他可以继承Profile中的方法

  {

    protected string _address1;                  //子类ExtendedProfile的属性

    protected string _address2;

    protected string _city;

    protected string _state;

    protected string _postal;

    protected string _description;

 public ExtendedProfile()                      //子类ExtendedProfile中属性的初始值

 {

   _address1 = "清华大学";

   _address2 = "清华大学物理实验室";

   _city = "北京";

   _state = "北京";

   _postal = "100024";

   _description = "教授";

 }

 public override void setPhonenumber(string phonenumber)           //继承类Profile中的setPhonenumber()方法

 {                                                                                                 //setPhonenumber()方法的重载

   _phonenumber = phonenumber;

 }

 public string getAddress1()          //子类ExtendedProfile中的方法getAddress1(),以下类推

 {

   return _address1;

 }

 public string getAddress2()

 {

   return _address2;

 }

 public void setAddress(string address1,string address2)

 {

   _address1 = address1;

   _address2 = address2;

 }

 public string getCity()

 {

   return _city;

 }

 public void setCity(string city)

 {

   _city = city;

 }

 public string getState()

 {

   return _state;

 }

 public void setState(string state)

 {

   _state = state;

 }

 public string getPostal()

 {

   return _postal;

 }

 public void setPostal(string postal)

 {

   _postal = postal;

 }

 public string getDescription()

 {

   return _description;

 }

 public void setDescription(string description)

 {

   _description = description;

 }

 public override void save()                //调用接口ISaveData()中的方法save(),save()方法的重载,由于多态性

 {                                                       //子类ExtendedProfile可以自定义并修改save()方法

   string _document = "d:\\myweb2\\saidy.xml";

   XmlTextWriter writer = null;           //保存为一个Xml文件

   try

   {

    writer = new XmlTextWriter(_document,null);

    writer.Formatting = Formatting.Indented;

    writer.WriteStartDocument(false);

    writer.WriteDocType("Profile",null,null,null);            //表示<!DOCTYPE Profile>

    writer.WriteStartElement("Profile");                         //生成根元素  

    writer.WriteElementString("firstname",_firstname);   //生成子元素  <firstname>_firstname</firstname>

    writer.WriteElementString("lastname",_lastname);

    writer.WriteElementString("phonenumber",_phonenumber);

    writer.WriteElementString("address1",_address1);

    writer.WriteElementString("address2",_address2);

    writer.WriteElementString("city",_city);

    writer.WriteElementString("state",_state);

    writer.WriteElementString("postal",_postal);

  writer.WriteEndElement();

  writer.Flush();

  writer.Close();

   }

   catch(Exception ee)

   {

     Console.WriteLine("Exception:{0}",ee.ToString());

   }

 }

}

}

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