/// <summary>
/// 重写基类方法，然后用base关键字调用基类方法
/// 间接实现在子类中调用事件
/// </summary>
/// <param name="e"></param>
protected override void OnShapeChanged(ShapeEventArgs e)
{
base.OnShapeChanged(e);
}
protected virtual void OnShapeChanged(ShapeEventArgs e)
{
EventHandler<ShapeEventArgs> handler = ShapeChanged;
if (handler != null)
{
handler(this, e);
}
}
private static void HandleShapeChanged(object sender, ShapeEventArgs e)
{
Shape s = (Shape)sender;
Console.WriteLine("Received event.Shape area is now {0}", e.NewArea);
s.Draw();
}
