CSharp: Observer Pattern in donet core 6

 

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using Geovin.Du.DuObserver.DuNewspaper.Publishers.Common; using Geovin.Du.DuObserver.DuNewspaper.Subscribers.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuObserver.DuNewspaper.Subscribers {       /// <summary>     /// 观察者模式 Observer Pattern 亦称： 事件订阅者、监听者、Event-Subscriber、Listener、Observer     /// </summary>     public class User : IUser     {           /// <summary>         ///         /// </summary>         private readonly decimal _availableMonthlySubscriptionAmount;         /// <summary>         ///         /// </summary>         /// <param name="name"></param>         /// <param name="username"></param>         /// <param name="availableMonthlySubscriptionAmount"></param>         public User(string name, string username, decimal availableMonthlySubscriptionAmount)         {             Name = name;             Username = username;             _availableMonthlySubscriptionAmount = availableMonthlySubscriptionAmount;         }         /// <summary>         ///         /// </summary>         public string Username { get; set; }         /// <summary>         ///         /// </summary>         public string Name { get; set; }         /// <summary>         ///         /// </summary>         /// <param name="newspaper"></param>         public void ReportSubscriptionPriceChange(Newspaper newspaper)         {             if (newspaper.MonthlyPrice > _availableMonthlySubscriptionAmount)             {                 newspaper.Unsubscribe(this);             }         }     } }        /// <summary>     /// 观察者模式 Observer Pattern 亦称： 事件订阅者、监听者、Event-Subscriber、Listener、Observer     /// </summary>     public interface IUser     {           /// <summary>         ///         /// </summary>         public string Username { get; set; }           /// <summary>         ///         /// </summary>         public string Name { get; set; }           /// <summary>         ///         /// </summary>         /// <param name="newspaper"></param>           void ReportSubscriptionPriceChange(Newspaper newspaper);     }         /// <summary>     /// 观察者模式 Observer Pattern 亦称： 事件订阅者、监听者、Event-Subscriber、Listener、Observer     /// </summary>     public class DailyMail : Newspaper     {           /// <summary>         ///         /// </summary>         public DailyMail()             : base("每日邮报", 5)         {         }     }      /// <summary>     /// 观察者模式 Observer Pattern 亦称： 事件订阅者、监听者、Event-Subscriber、Listener、Observer     /// </summary>     public static class NewspaperExecutor     {           /// <summary>         ///         /// </summary>         public static void Execute()         {             ConsoleExtension.WriteSeparator("观察者模式 Observer Pattern ;Newspaper demo");               var dailyMail = new DailyMail();             dailyMail.Subscribe(new User("涂聚文", "geovindu", 5));             dailyMail.Subscribe(new User("Geovin Du", "du", 10));             dailyMail.Subscribe(new User("涂氏", "geovin", 6));               Console.WriteLine();             dailyMail.MonthlyPrice = 6;               Console.WriteLine();             dailyMail.MonthlyPrice = 8;         }     }

　　

调用：

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1	Geovin.Du.DuObserver.DuNewspaper.NewspaperExecutor.Execute();

　　

输出：

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观察者模式 Observer Pattern ;Newspaper demo -------------------------------------------------- 涂聚文 是否订阅 每日邮报 报纸. Geovin Du 是否订阅 每日邮报 报纸. 涂氏 是否订阅 每日邮报 报纸.   每日邮报 报纸每月价格更改为 ￥6.00. 涂聚文 未订阅 每日邮报 报纸.   每日邮报 报纸每月价格更改为 ￥8.00. 涂氏 未订阅 每日邮报 报纸.