CSharp: Lazy Load Pattern in donet core 6

 

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuLazyLoad.DuVirtualProxy {       /// <summary>     /// Lazy Load Pattern     /// </summary>     public class College     {           /// <summary>         /// 序号         /// </summary>         public int Id { get; init; }         /// <summary>         /// 图书馆信息         /// </summary>         public virtual Library? Library { get; set; }         /// <summary>         ///         /// </summary>         public void ShowDetails() =>             Console.WriteLine(                 $"大学图书馆有 {Library!.NumberOfBooks} 本书 " +                 $"创建时间为：{Library.EstablishmentDate.ToShortDateString()}.");     }   }   using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuLazyLoad.DuVirtualProxy {     /// <summary>     /// Lazy Load Pattern     /// </summary>     public class CollegeFactory     {           /// <summary>         ///         /// </summary>         /// <param name="id"></param>         /// <returns></returns>         public College CreateFromId(int id) => new ProxyCollege(id);     }   }     using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Geovin.Du.DuLazyLoad.DuVirtualProxy {       /// <summary>     ///     /// </summary>     public class ProxyCollege : College     {           /// <summary>         /// Lazy Load Pattern         /// </summary>         /// <param name="id"></param>         public ProxyCollege(int id)         {             Id = id;             Console.WriteLine("学院信息初始化完成.");         }         /// <summary>         ///         /// </summary>         public override Library? Library         {             get             {                 if (base.Library == null)                 {                     base.Library = new Library();                 }                   return base.Library;             }             set => base.Library = value;         }         /// <summary>         ///         /// </summary>         /// <param name="obj"></param>         /// <returns></returns>         public override bool Equals(object? obj)         {             if (obj is not College college)             {                 return false;             }               return college.Id == Id;         }         /// <summary>         ///         /// </summary>         /// <returns></returns>         public override int GetHashCode() => Id.GetHashCode();     }   }     using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using Geovin.Du.BuildingBlocks;     namespace Geovin.Du.DuLazyLoad.DuVirtualProxy {       /// <summary>     /// Lazy Load Pattern     /// </summary>     public static class VirtualProxyExecutor     {         public static void Execute()         {             ConsoleExtension.WriteSeparator("延迟加载模式 Lazy Load Pattern--Virtual proxy demo");               var collegeFactory = new CollegeFactory();             var college = collegeFactory.CreateFromId(1);               // College library shouldn't have been constructed before calling ShowDetails method.             Console.WriteLine("给我更多关于这所大学的细节!");             college.ShowDetails();         }     }   }

　　

调用：

?

1	Geovin.Du.DuLazyLoad.DuVirtualProxy.VirtualProxyExecutor.Execute();

　　

输出：

?

1 2 3 4 5 6

延迟加载模式 Lazy Load Pattern--Virtual proxy demo -------------------------------------------------- 学院信息初始化完成. 给我更多关于这所大学的细节! 加载库... 大学图书馆有 210000 本书 创建时间为：2008/5/28.