C#基础：多态：基类可以定义并实现虚(virtual)方法，派生类可以重写(override)这些方法

原理：基类可以定义并实现虚(virtual)方法，派生类可以重写(override)这些方法

实例代码：

class Shape

{

//

public int X{get;private set; }

public int Y{get;private set;}

public int Height{get;set;}

public int Width{get;set;}

//

public virtual void Draw()

{

Console.WriteLine("Performing base class drawing tasks");

}

}

class Circle : Shape

{

public override void Draw()

{

// Code to draw a circle...

Console.WriteLine("Drawing a circle");

base.Draw();

}

}

class Rectangle : Shape

{

public override void Draw()

{

// Code to draw a rectangle...

Console.WriteLine("Drawing a rectangle");

base.Draw();

}

}

class Triangle : Shape

{

public override void Draw()

{

// Code to draw a triangle...

Console.WriteLine("Drawing a triangle");

base.Draw();

}

}

class Program

{

static void Main(string[] args)

{

List<Shape> shapes = new List<Shape>();

shapes.Add(new Rectangle());

shapes.Add(new Triangle());

shapes.Add(new Circle());

foreach (Shape s in shapes)

{

s.Draw();

}

Console.WriteLine("press any key to exit.");

Console.ReadKey();

}

}