protected void Page_Load(object sender, EventArgs e)
{person[] p = new person[2];chinese p1 = new chinese();jpan p2 = new jpan();p[0] = p1;p[1] = p2;Response.Write(p[0].SayHi()); //调用的方法时取决于自己是什么对象Response.Write(p[1].SayHi());
}public class person
{public virtual string SayHi() //父类方法使用virtual表示该方法是虚方法
    {return "人类";}
}public class chinese : person
{public override string SayHi() //子类方法使用override表示该方法是重写虚方法
    {return "中国人";}
}public class jpan : person
{public override string SayHi() // override
    {return "日本人";}
}

protected void Page_Load(object sender, EventArgs e)
{//抽象类不能被实例化 只能实例化子类对象xingzhuang y = new yuan(5);double mianji = y.mianji();double zhouchang = y.zhouchang();Response.Write("半径为5的原型面积为：" + mianji + "，周长：" + zhouchang);xingzhuang ju = new juxing(10, 20);double mianji1 = ju.mianji();double zhouchang1 = ju.zhouchang();Response.Write("高为10的宽为20的矩形面积为：" + mianji1 + "，周长：" + zhouchang1);
}public abstract class xingzhuang //被标记为abstract的类称为抽象类
{public string Name { get; set; } //抽象类中可以包含实例成员，并且实力成员可以不被子类实现。public abstract double mianji(); //抽象方法必须标记为abstract，并且不能有任何实现，必须在抽象类中。public abstract double zhouchang(); //抽象成员的访问修饰符不能是private
}public class yuan : xingzhuang
{public double R { get; set; }public yuan(double r){this.R = r;}public override double mianji() //子类继承抽象类后必须把父类中所有抽象成员重写
    {return Math.PI * this.R * this.R;}public override double zhouchang() //子类继承抽象类后必须把父类中所有抽象成员重写
    {return 2 * Math.PI * this.R;}
}public class juxing : xingzhuang
{public double width { get; set; }public double height { get; set; }public juxing(double height, double width){this.height = height;this.width = width;}public override double mianji() //子类继承抽象类后必须把父类中所有抽象成员重写
    {return this.height * this.width;}public override double zhouchang() //子类继承抽象类后必须把父类中所有抽象成员重写
    {return (this.height + this.width) * 2;}
}

class Program
{static void Main(string[] args){while (true){Console.WriteLine("请输入要进入的磁盘");string path = Console.ReadLine();Console.WriteLine("请输入要进入的文件");string fileName = Console.ReadLine();FileFather f = getFile(fileName, path + fileName);f.OpenFile(); //打开一个文件取决于输入一个什么文件
Console.ReadKey();}}public static FileFather getFile(string fileName, string fullName) //简单工厂形式返回父类
    {string ext = Path.GetExtension(fileName);FileFather f;switch (ext){case ".txt":f = new txtPath(fullName);break;case ".jpg":f = new jpgPath(fullName);break;default:f = null;break;}return f;}
}public abstract class FileFather //抽象父类
{public string fileName { get; set; } //文件全路径public FileFather(string fileName) //构造函数 自己不能用
    {this.fileName = fileName;}public abstract void OpenFile(); //抽象方法
}public class txtPath : FileFather
{public txtPath(string fileName) //继承父类构造函数: base(fileName){}public override void OpenFile() //子类重写
    {ProcessStartInfo psi = new ProcessStartInfo(fileName);//使用进程打开指定文件Process pro = new Process();pro.StartInfo = psi;pro.Start();}
}public class jpgPath : FileFather
{public jpgPath(string fileName): base(fileName){}public override void OpenFile(){ProcessStartInfo psi = new ProcessStartInfo(fileName);Process pro = new Process();pro.StartInfo = psi;pro.Start();}
}

protected void Page_Load(object sender, EventArgs e)
{//将P传输给对方电脑person p = new person();p.name = "张三";p.age = 18;p.gender = '男';using (FileStream sw = new FileStream(@"d:\11.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite))//序列化到目标文件
    {//开始序列化对象BinaryFormatter bf = new BinaryFormatter();bf.Serialize(sw, p); //要被序列化的对象 sw.Write 自动完成
    }person per = new person();//接收对方发过来的二进制 反序列化对象using (FileStream sr = new FileStream(@"d:\11.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite)){BinaryFormatter bf1 = new BinaryFormatter();per = (person)bf1.Deserialize(sr);}Response.Write(per.name + per.age + per.gender);
}[Serializable] //将这个类标记为可被序列化
public class person
{public string name { get; set; }public int age { get; set; }public char gender { get; set; }
}

public interface IFly
{//成员不允许添加访问修饰符，默认就是publicstring name { get; set; } //接口可以有方法、属性、所引器。void Fly(); //不可以有方法体
}public class father
{}public class person : father, IFly //先写类 后写接口
{public string name { get; set; }public void Fly(){}
}

//用来解决方法重名问题
class Program
{static void Main(string[] args){Ifly fly = new Birad();fly.Fly(); //接口的Briad bid = new Briad();bid.Fly(); //自己的
    }
}public class Birad : Ifly //鸟类继承接口ifly
{public string Fly() //类自己的方法
    {return "fly";}public string Ifly.Fly(){ //接口的方法return "ifly11111";}
}public interface Ifly //定义接口 fly方法
{string Fly();
}

try
{int number = 10; //可能出错的代码块
}catch (Exception ex)
{Console.WriteLine(ex.Message);//错误信息throw new Exception("错误"); //抛出异常
}