static void Main()
{
//协变，子类传递给父类，存在安全的隐式转换
//逆变，父类传递给子类
//一个可变性和子类到父类转换的方向一样，就称作协变；而如果和子类到父类的转换方向相反，就叫抗变！
IIndex<Rectangle> rectangles = RectangleCollection.GetRectangles();
//协变,把Rectangle assign to Shape
IIndex<Shape> shapes = rectangles;
for (int i = 0; i < shapes.Count; i++)
{
Console.WriteLine(shapes[i]);
}
IDisplay<Shape> shapeDisplay = new ShapeDisplay();
shapeDisplay.Show(rectangles[0]);
IDisplay<Rectangle> rectangleDisplay = shapeDisplay;
rectangleDisplay.Show(rectangles[0]);
Console.ReadLine();
}
static void Main()
{
Shape shape = new Rectangle(200, 120, Color.Blue);
// Shape shape = new Triangle(180, 250, Color.Orange);
ShapeDisplay shapeDisplay = new ShapeDisplay(shape);
Application.Run(shapeDisplay);
}
private static void 泛型接口的抗变()
{
IDisplay <Shape> shapeDisplay = new ShapeDisplay();
IDisplay <Rectangle> rectangleDisplay = shapeDisplay;
IIndex <Rectangle> rectangles = RectangleCollection.GetRectangles();
shapeDisplay.Show(rectangles[0]);
rectangleDisplay.Show(rectangles[0]);
}
public override void Draw(ShapeDisplay sd, Graphics canvas)
{
base.Draw(sd, canvas);
int xStart = sd.Xoffset;
int yStart = sd.Yoffset + Height;
canvas.DrawLine(pen, xStart, yStart, xStart + Basis, yStart);
canvas.DrawLine(pen, xStart, yStart, xStart + Basis / 2, yStart - Height);
canvas.DrawLine(pen, xStart + Basis, yStart, xStart + Basis / 2, yStart - Height);
}
public override void Draw(ShapeDisplay sd, Graphics canvas)
{
base.Draw(sd, canvas);
// determine position for drawing
int xStart = sd.Xoffset;
int yStart = sd.Yoffset + this.Height;
canvas.DrawLine(pen, xStart, yStart, xStart, yStart - Height);
canvas.DrawLine(pen, xStart, yStart, xStart + Width, yStart);
canvas.DrawLine(pen, xStart, yStart - Height, xStart + Width, yStart - Height);
canvas.DrawLine(pen, xStart + Width, yStart, xStart + Width, yStart - Height);
}
static void Main()
{
IIndex<Rectangle> rectangles = RectangleCollection.GetRectangles();
IIndex<Shape> shapes = rectangles;
for (int i = 0; i < shapes.Count; i++)
{
Console.WriteLine(shapes[i]);
}
IDisplay<Shape> shapeDisplay = new ShapeDisplay();
IDisplay<Rectangle> rectangleDisplay = shapeDisplay;
rectangleDisplay.Show(rectangles[0]);
Console.ReadKey();
}
static void Main(string[] args)
{
Rectangle[] Rectangles = new Rectangle[3]
{
new Rectangle { Heigh=2, Width=5},
new Rectangle { Heigh=2, Width=5},
new Rectangle { Heigh=2, Width=5}
};
//Class1.Example();
//Console.WriteLine("User-Perferences:BackColor is:" + UserPreferences.BackColor.ToString() + "");
//Console.ReadLine();
IDisplay<Shape> shapeDisplay = new ShapeDisplay();
IDisplay<Rectangle> rectangleDisplay = shapeDisplay;
rectangleDisplay.Show(Rectangles[0]);
}
public void TestRectangleCollection()
{
// 协变
IIndex <Rectangle> rectangles = RectangleCollection.GetRectangles();
IIndex <Shape> shapes = rectangles;
for (int i = 0; i < shapes.Count; i++)
{
Debug.WriteLine(shapes[i]);
}
// 抗变
IDisplay <Shape> shapeDisplay = new ShapeDisplay();
IDisplay <Rectangle> rectangleDisplay = shapeDisplay;
Debug.WriteLine(rectangleDisplay.Show(rectangles[0]));
}
static void Main()
{
IIndex<Rectangle> rectangles = RectangleCollection.GetRectangles();
IIndex<Shape> shapes = rectangles;
for (int i = 0; i < shapes.Count; i++)
{
Console.WriteLine(shapes[i]);
}
IDisplay<Shape> shapeDisplay = new ShapeDisplay();
IDisplay<Rectangle> rectangleDisplay = shapeDisplay;
/*Because IDisplay<T> is contra-variant, it is possible to assign the result to
IDisplay<Rectangle>, where Rectangle derives from Shape. This time the methods of the interface
define only the generic type as input*/
rectangleDisplay.Show(rectangles[0]);
}
public virtual void Draw(ShapeDisplay sd, Graphics canvas)
{
// we define a uniform pen size for all shapes
pen = new Pen(this.edgeColor, 3);
}
public override void Draw1(ShapeDisplay sd, Graphics canvas)
{
foreach (var item in)
}
public virtual void Draw1(ShapeDisplay sd, Graphics canvas)
{
pen = new Pen(this.randkleur, 3);
}
