CSharp: Chain of Responsibility Pattern in donet core 6

 

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common {       /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// 采购     /// </summary>     public abstract class Approver     {           /// <summary>         ///         /// </summary>         protected Approver? Next { get; private set; }         /// <summary>         ///         /// </summary>         /// <param name="next"></param>         /// <returns></returns>         public Approver RegisterNext(Approver next)         {             Next = next;             return Next;         }         /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public abstract void Approve(Purchase purchase);     } }   using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common {     /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// 审批     /// </summary>     public class Purchase     {           /// <summary>         /// 数量         /// </summary>         public int Number { get; set; }         /// <summary>         /// 费用         ///</summary>         public decimal Cost { get; set; }         /// <summary>         /// 审批         /// </summary>         public string Purpose { get; set; } = string.Empty;     } }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using static System.Net.Mime.MediaTypeNames;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers {     /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public class Director : Approver     {           /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public override void Approve(Purchase purchase)         {             if (purchase.Cost < 1000)             {                 Console.WriteLine($"董事批准了这笔购买 #{purchase.Number} 这成本 {purchase.Cost:C}");                 return;             }               Next?.Approve(purchase);         }     } }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers {     /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public class ExecutiveMeeting : Approver     {           /// <summary>         ///         /// </summary>         public static readonly ExecutiveMeeting Instance = new();         /// <summary>         ///         /// </summary>         private ExecutiveMeeting()         {         }         /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public override void Approve(Purchase purchase) =>             Console.WriteLine(                 $"这次采购#{purchase.Number} 成本是 {purchase.Cost:C}  " +                 "需要召开一次行政会议才能得到批准.");     }   }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using static System.Net.Mime.MediaTypeNames;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers {       /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public class Manager : Approver     {           /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public override void Approve(Purchase purchase)         {             if (purchase.Cost < 500)             {                 Console.WriteLine($"经理批准了这笔购买 #{purchase.Number} 成本是 {purchase.Cost:C}");                 return;             }               Next?.Approve(purchase);         }     } }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using static System.Net.Mime.MediaTypeNames;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers {       /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public class President : Approver     {           /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public override void Approve(Purchase purchase)         {             if (purchase.Cost < 5000)             {                 Console.WriteLine($"董事长批准了购买 #{purchase.Number} 成本是 {purchase.Cost:C}");                 return;             }               Next?.Approve(purchase);         }     }   }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using static System.Net.Mime.MediaTypeNames;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers {       /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public class VicePresident : Approver     {           /// <summary>         ///         /// </summary>         /// <param name="purchase"></param>         public override void Approve(Purchase purchase)         {             if (purchase.Cost < 2000)             {                 Console.WriteLine($"副董事长批准了这次购买 #{purchase.Number} 成本是 {purchase.Cost:C}");                 return;             }               Next?.Approve(purchase);         }     }   }   using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Common; using Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.Handlers; using Geovin.Du.BuildingBlocks; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval {       /// <summary>     /// 责任链模式Chain of Responsibility Pattern 亦称： 职责链模式、命令链、CoR、Chain of Command、Chain of Responsibility     /// </summary>     public static class PurchaseApprovalExecutor     {           /// <summary>         ///         /// </summary>         public static void Execute()         {             ConsoleExtension.WriteSeparator("责任链模式Chain of Responsibility Pattern--Purchase approval demo");               Approver manager = new Manager();             Approver director = new Director();             Approver vicePresident = new VicePresident();             Approver president = new President();               manager                 .RegisterNext(director)                 .RegisterNext(vicePresident)                 .RegisterNext(president)                 .RegisterNext(ExecutiveMeeting.Instance);               var lowCostPurchase = new Purchase { Number = 1, Cost = 400, Purpose = "白板上购买." };             var mediumCostPurchase = new Purchase { Number = 2, Cost = 3000, Purpose = "笔记本电脑购买e." };             var highCostPurchase = new Purchase { Number = 3, Cost = 11500, Purpose = "汽车的购买." };               manager.Approve(lowCostPurchase);             manager.Approve(mediumCostPurchase);             manager.Approve(highCostPurchase);         }     } }

　　调用：

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1	Geovin.Du.DuChainOfResponsibility.DuPurchaseApproval.PurchaseApprovalExecutor.Execute();

　　

输出：、

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Hello, Geovin Du! 学习 .net 6   责任链模式Chain of Responsibility Pattern--Purchase approval demo -------------------------------------------------- 经理批准了这笔购买 #1 成本是 ￥400.00 董事长批准了购买 #2 成本是 ￥3,000.00 这次采购#3 成本是 ￥11,500.00  需要召开一次行政会议才能得到批准.