static void Main(string[] args)
{
Heater heater = new Heater();
Screen screen = new Screen();
Alarm alarm = new Alarm();
heater.Register(screen); // 注册显示器
heater.Register(alarm); // 注册热水器
heater.BoilWater(); // 烧水
heater.UnRegister(alarm); // 取消报警器的注册
heater.BoilWater(); // 再次烧水
Console.WriteLine();
Console.WriteLine("/*************推模式********************/");
/*************推模式********************/
Heater2 heater2 = new Heater2();
Screen2 screen2 = new Screen2();
heater2.Register(screen2); // 注册显示器
heater2.BoilWater(); // 烧水
Console.WriteLine();
Console.WriteLine("/*************拉模式********************/");
/*************拉模式********************/
Heater3 heater3 = new Heater3();
Screen3 screen3 = new Screen3();
heater3.Register(screen3); // 注册显示器
heater3.BoilWater(); // 烧水
Console.ReadKey();
}
private bool isDisplayedType = false; // 标记变量，标示是否已经打印过
public void Update(IObservale3 obj)
{
// 这里存在一个向下转换(由继承体系中高级别的类向低级别的类转换)
Heater3 heater = (Heater3)obj;
// 打印产地和型号，只打印一次
if (!isDisplayedType)
{
Console.WriteLine("{0} - {1}: ", heater.Area, heater.Type);
Console.WriteLine();
isDisplayedType = true;
}
if (heater.Temperature < 100)
{ // 通过热水器引用heater获取温度
Console.WriteLine(
String.Format("Alarm".PadRight(7) + "：水快烧开了，当前温度：{0}。",
heater.Temperature));
}
else
{
Console.WriteLine(
String.Format("Alarm".PadRight(7) + "：水已经烧开了！！"));
}
}