/// <summary>
/// 关联
/// </summary>
public static void Init()
{
var buyer = new Buyer();
IphoneX phone = new IphoneX()
{
Price = 10000
};
phone.DiscountHandler += buyer.Buy;
//改了属性的价格，降价了，此时会触发事件的执行
phone.Price = 2000;
}
//参数需要和eventhandler参数一致
public void Buy(object?sender, EventArgs e)
{
IphoneX phone = (IphoneX)sender;
}
