1.静态类、静态方法、静态属性
2.抽象类
3.接口
4.向上转型和向下转型
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public class YourClass//实例类可以定义静态方法
private string aa;//实例成员
public static string bb;//静态成员
public YourClass( )
{
Console.WriteLine( "实例构造函数...." );
}
static YourClass( )
{
Console.WriteLine( "静态构造函数....");
}
public static void FunctionStatic()
{
Console.WriteLine( "静态方法.....");//静态方法不能访问（但可以自定义）实例成员，也不能访问实例方法。但可以访问静态成员
}
public void FunctionInstance( )//实例方法可以访问类成员，包括静态和实例成员
{
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static void Main( string[ ] args )
{
YourClass yc1=new YourClass();
YourClass yc2=new YourClass();
YourClass.FunctionStatic();//静态方法通过类名调用，除了构造函数在创建对象时执行
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public static class StaticClass//静态类的所有成员都必须是static
{
{
}
抽象类Graphic.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public abstract class Graphic//抽象类不能被实例化
{
protected double[ ] bianChange;//实例成员
//产品设计说明书
public abstract double GetLength( );//抽象方法一定要定义抽象类当中
public abstract double GetArea( );
public Graphic( int length )//实例方法
{
bianChange = new double[ length ];
}
public virtual void Show()
{
Console.WriteLine( "这是图形的虚方法.....");
}
}
}
实现类Circle.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public class Circle:Graphic//字类要实现父类所有的抽象成员
{
public Circle( int length )
: base( length )//访问父类构造函数
{
base.bianChange[ 0 ] = 10;
}
//计算面积
public override double GetArea( )//重写抽象方法override
{
return base.bianChange[ 0 ] * base.bianChange[ 0 ] * Math.PI;
}
//计算周长
public override double GetLength( )
{
return base.bianChange[ 0 ] * 2 * Math.PI;
}
public override void Show( )
{
Console.WriteLine( "圆形的重写方法.....");
}
}
}
Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static void Main( string[ ] args )
{
Circle circle = new Circle( 1 );
double mj = circle.GetArea( );
Console.WriteLine( "面积：{0}平方米" , mj );
}
}
}
接口是通过类实现的，如同产品要根据产品说明书进行设计实现。两者有关联但不相同。
接口：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public interface IUSB
{
void Write( );//接口成员默认为public，接口只能定义不能实现{}
void Read( );
}
}
实现类：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public class MP3:IUSB//实现接口所有方法
{
public void Write( )
{
Console.WriteLine( "下载歌曲");
}
public void Read( )
{
Console.WriteLine( "播放歌曲" );
}
}
}
主程序：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static void Main( string[ ] args )
{
IUSB usb = new MP3( );
usb.Read( );//调用MP3类的Read方法
}
}
}
eg:
接口：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public interface IMobile
{
void Call( );//打电话
void Message( );//发短信
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public interface INet
{
void Internet( );//上网
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public interface IIntellMobile//智能手机
{
void Pay( );//支付
void Chat( ); //聊天
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public interface IShouJi : INet , IMobile , IIntellMobile//接口可多继承父接口
{
}
}
实现：可继承多个接口
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public abstract class Mobile: IMobile//抽象类继承加实现接口
{
public void Call( )
{
Console.WriteLine( "打电话....");
}
public void Message( )
{
Console.WriteLine( "发短信...." );
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public class TraditionMobile:Mobile,INet//实现上网接口，先写父类，再写接口
{
public void Internet( )
{
Console.WriteLine( "网上冲浪.....");
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
public class IntellMobile:Mobile,IShouJi//实现剩余的接口方法
{
public void Pay( )
{
Console.WriteLine("支付宝......");
}
public void Chat( )
{
Console.WriteLine( "聊天......");
}
public void Internet( )
{
Console.WriteLine( "网址冲浪....");
}
}
}
主程序：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static void Main( string[ ] args )
{
IntellMobile im = new IntellMobile( );
im.Chat( );
}
}
}
