关于委托，事件和类的设计准则

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Demo
{
    /// <summary>
    /// 报警处理器：用于热水器及其关联的报警器
    /// </summary>
    /// <param name="heater">热水器</param>
    /// <param name="alarmer">报警器</param>
    public delegate void AlarmHandler(WaterHeater heater, TemperatureAlarmer alarmer);

    /// <summary>
    /// 温度报警器：设定当前温度和报警温度；
    /// 在超过报警温度后会触发事件 TemperatureOverflow，交给挂接报警器的设备处理
    /// </summary>
    public class TemperatureAlarmer
    {
        private float temperature_current, temperature_alarm;
        /// <summary>
        /// 在超过报警温度后会触发事件 TemperatureOverflow，交给挂接报警器的设备处理,如热水器
        /// </summary>
        public event Action TemperatureOverflow;

        //温度检查：超过报警温度后启动报警引擎
        private void TemperatureCheck()
        {
            if (temperature_current > temperature_alarm)
                TemperatureOverflow();
        }
        
        public TemperatureAlarmer()
        {
            temperature_current = 0f;
            temperature_alarm = 95f;
        }
        /// <summary>
        /// 属性：加热温度，范围35~100
        /// </summary>
        public float TemperaturCurrent
        {
            get { return temperature_current; }
            set
            {
                temperature_current = value > 100 ? 100 : value;
                temperature_current = value < 35 ? 35 : value;
                TemperatureCheck();
            }
        }
        /// <summary>
        /// 属性：报警温度，范围35~100
        /// </summary>
        public float TemperaturAlarm
        {
            get
            { return temperature_alarm; }
            set
            {
                temperature_alarm = value > 100 ? 100 : value;
                temperature_alarm = value < 35 ? 35 : value;
                TemperatureCheck();
            }
        }

    }

    /// <summary>
    /// 热水器，属于加热器，需要温度报警器
    /// </summary>
    public class WaterHeater
    {
        public string TradeMark { get; set; }
        public string Company { get; set; }
        public TemperatureAlarmer heaterAlarmer;
        /// 热水器报警事件，将处理权交给用户处理
        public event AlarmHandler TemperatureOverflow;
        /// 可以绑定更换掉默认的温度报警器
        public void BindAlarmer(TemperatureAlarmer alarmer)
        {
            this.heaterAlarmer = alarmer;
        }
        public WaterHeater()
        {
            heaterAlarmer = new TemperatureAlarmer();
            heaterAlarmer.TemperatureOverflow += () =>
            {
                TemperatureOverflow(this, heaterAlarmer);
            };
        }

        /// 对加热器进行加热，最高到100度,将温度增加到指定值
        public void Heat(float temperature)
        {
            heaterAlarmer.TemperaturCurrent = temperature;
        }

        public override string ToString()
        {
            return $"{this.Company},{this.TradeMark},{heaterAlarmer.TemperaturCurrent}/{heaterAlarmer.TemperaturAlarm}";
        }
    }

    /*
海信,?新婚之夜,0/95
Overflow:海信,?新婚之夜,88/80
海信,?新婚之夜,88/80
海信,?新婚之夜,95/95
海信,?新婚之夜,95/95
海信,?新婚之夜,90/95
    */
    public class RunMyApp
    {
        static void Main(string[] args)
        {
            WaterHeater HisenseWarmer = new WaterHeater();
            HisenseWarmer.Company = "海信";
            HisenseWarmer.TradeMark = "©新婚之夜";
            HisenseWarmer.TemperatureOverflow += (heater, e) => Console.WriteLine("Overflow:" + HisenseWarmer);
            Console.WriteLine(HisenseWarmer);//

            HisenseWarmer.Heat(88);//
            HisenseWarmer.heaterAlarmer.TemperaturAlarm = 80;//
            Console.WriteLine(HisenseWarmer);

            //更换第三方温度报警器，具有更高级的自我调节温度功能，也就是保证不超过报警温度
            TemperatureAlarmer OmronAlarmer = new TemperatureAlarmer();
            OmronAlarmer.TemperatureOverflow += () =>
            {
                OmronAlarmer.TemperaturCurrent = OmronAlarmer.TemperaturAlarm;
            };
            HisenseWarmer.BindAlarmer(OmronAlarmer);
            HisenseWarmer.Heat(96);
            Console.WriteLine(HisenseWarmer);

            OmronAlarmer.TemperaturCurrent = 100;
            Console.WriteLine(HisenseWarmer);

            HisenseWarmer.Heat(90);
            Console.WriteLine(HisenseWarmer);

            Console.ReadKey();
        }
    }
}