求救,new关键字隐藏父类的问题?
class Shape{
public virtual void Draw()
{
Console.WriteLine("Shape.Draw") ;
}
}
class Rectangle : Shape
{
public new void Draw()
{
Console.WriteLine("Rectangle.Draw");
}
}
class Square : Rectangle
{
//这里不用 override
public new void Draw()
{
Console.WriteLine("Square.Draw");
}
}
class MainClass
{
static void Main(string[] args)
{
Console.WriteLine("Using Polymorphism:");
Shape[] shp = new Shape[3];
Rectangle rect = new Rectangle();
shp[0] = new Shape();
shp[1] = rect;
shp[2] = new Square();
shp[0].Draw();
shp[1].Draw();
shp[2].Draw();
Console.WriteLine("Using without Polymorphism:");
rect.Draw();
Square sqr = new Square();
sqr.Draw();
}
}
Output:
Using Polymorphism
Shape.Draw
Shape.Draw
Shape.Draw
Using without Polymorphism:
Rectangle.Draw
Square.Draw
上面的代码中我有一个问题不太明白:
shp[0] = new Shape();
shp[1] = rect;
shp[2] = new Square();
shp[0].Draw();
shp[1].Draw();
shp[2].Draw();
和
rect.Draw();
Square sqr = new Square();
sqr.Draw();
都是先通过实例化对象后调用,这两个有什么区别?不是说隐藏后的基类方法只能通过基类访问调用吗?
小弟初学,还望各位大侠帮忙帮我解释解释!在此先谢过!
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