在Avalonia项目中使用MediatR和MS.DI库实现事件驱动通信

九天猎人  金牌会员 | 2024-5-12 20:43:58 | 显示全部楼层 | 阅读模式
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大家好，我是沙漠尽头的狼！
AvaloniaUI是一个强大的跨平台.NET客户端开辟框架，让开辟者能够针对Windows、Linux、macOS、Android和iOS等多个平台构建应用程序。在构建复杂的应用程序时，模块化和组件间的通信变得尤为紧张。Prism框架提供了模块化的开辟方式，支持插件的热拔插，而MediatR则是一个实现了中介者（Mediator）模式的事件订阅发布框架，非常适实用于模块之间以及模块与主程序之间的通信。
本文重点是介绍MediatR，它 是 .NET 中的开源简单中介者模式实现。它通过一种历程内消息传递机制（无其他外部依赖），进行哀求/相应、命令、查询、通知和事件的消息传递，并通过泛型来支持消息的智能调度。开源库地址是 https://github.com/jbogard/MediatR。
本文将详细介绍怎样在Avalonia项目中使用MediatR和Microsoft的依赖注入（MS.DI）库来实现事件驱动的通信。

0. 基础知识准备-MediatR的基本用法

MediatR中有两种消息传递的方式：

  • Request/Response，用于一个单独的Handler。
  • Notification，用于多个Handler。
Request/Response

Request/Response 有点类似于 HTTP 的 Request/Response，发出一个 Request 会得到一个 Response。
Request 消息在 MediatR 中，有两种类型：

  • IRequest 返回一个T类型的值。
  • IRequest 不返回值。
对于每个 request 类型，都有相应的 handler 接口：

  • IRequestHandler 实现该接口并返回 Task<U>
  • RequestHandler 继承该类并返回 U
  • IRequestHandler 实现该接口并返回 Task
  • AsyncRequestHandler 继承该类并返回 Task
  • RequestHandler 继承该类不返回
Notification

Notification 就是通知，调用者发出一次，然后可以有多个处置惩罚者到场处置惩罚。

1. 准备工作

首先，确保你的Avalonia项目中已经安装了必要的NuGet包。你将必要Prism.DryIoc.Avalonia作为依赖注入容器，以及MediatR来处置惩罚事件的发布和订阅。此外，为了将MediatR集成到DryIoc容器中，你还必要DryIoc.Microsoft.DependencyInjection包（这里感谢网友寒提供的技能解答）。
在项目的.csproj文件或NuGet包管理器中添加以下引用：
  1. <PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />
复制代码
2. 配置容器和注册服务

在Avalonia项目中，你必要配置DryIoc容器以使用Microsoft的DI扩展，并注册MediatR服务。这通常在你的主启动类（如App.axaml.cs）中完成。
以下是配置容器和注册服务的示例代码：
  1. namespace CodeWF.Tools.Desktop;public class App : PrismApplication{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> // 省略了模块注入等和主题无关的代码，有兴趣源码在文末可查<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> ///<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  /// 1、DryIoc.Microsoft.DependencyInjection低版本可不要这个方法（5.1.0及以下）<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> /// 2、高版本必须，否则会抛出非常：System.MissingMethodException:“Method not found: 'DryIoc.Rules DryIoc.Rules.WithoutFastExpressionCompiler()'.”<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> /// 参考issues：https://github.com/dadhi/DryIoc/issues/529<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  12. <PackageReference Include="MediatR" Version="12.2.0" />  
  13. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> ///<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  14. <PackageReference Include="MediatR" Version="12.2.0" />  
  15. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  ///<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  16. <PackageReference Include="MediatR" Version="12.2.0" />  
  17. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  protected override Rules CreateContainerRules()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  18. <PackageReference Include="MediatR" Version="12.2.0" />  
  19. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  20. <PackageReference Include="MediatR" Version="12.2.0" />  
  21. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  22. <PackageReference Include="MediatR" Version="12.2.0" />  
  23. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return Rules.Default.WithConcreteTypeDynamicRegistrations(reuse: Reuse.Transient)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  24. <PackageReference Include="MediatR" Version="12.2.0" />  
  25. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  26. <PackageReference Include="MediatR" Version="12.2.0" />  
  27. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  28. <PackageReference Include="MediatR" Version="12.2.0" />  
  29. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  30. <PackageReference Include="MediatR" Version="12.2.0" />  
  31. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />.With(Made.Of(FactoryMethod.ConstructorWithResolvableArguments))<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  32. <PackageReference Include="MediatR" Version="12.2.0" />  
  33. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  34. <PackageReference Include="MediatR" Version="12.2.0" />  
  35. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  36. <PackageReference Include="MediatR" Version="12.2.0" />  
  37. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  38. <PackageReference Include="MediatR" Version="12.2.0" />  
  39. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />.WithFuncAndLazyWithoutRegistration()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  40. <PackageReference Include="MediatR" Version="12.2.0" />  
  41. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  42. <PackageReference Include="MediatR" Version="12.2.0" />  
  43. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  44. <PackageReference Include="MediatR" Version="12.2.0" />  
  45. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  46. <PackageReference Include="MediatR" Version="12.2.0" />  
  47. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />.WithTrackingDisposableTransients()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  48. <PackageReference Include="MediatR" Version="12.2.0" />  
  49. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  50. <PackageReference Include="MediatR" Version="12.2.0" />  
  51. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  52. <PackageReference Include="MediatR" Version="12.2.0" />  
  53. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  54. <PackageReference Include="MediatR" Version="12.2.0" />  
  55. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />//.WithoutFastExpressionCompiler()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  56. <PackageReference Include="MediatR" Version="12.2.0" />  
  57. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  58. <PackageReference Include="MediatR" Version="12.2.0" />  
  59. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  60. <PackageReference Include="MediatR" Version="12.2.0" />  
  61. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  62. <PackageReference Include="MediatR" Version="12.2.0" />  
  63. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />.WithFactorySelector(Rules.SelectLastRegisteredFactory());<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  64. <PackageReference Include="MediatR" Version="12.2.0" />  
  65. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  66. <PackageReference Include="MediatR" Version="12.2.0" />  
  67. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> protected override IContainerExtension CreateContainerExtension()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  68. <PackageReference Include="MediatR" Version="12.2.0" />  
  69. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  70. <PackageReference Include="MediatR" Version="12.2.0" />  
  71. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  72. <PackageReference Include="MediatR" Version="12.2.0" />  
  73. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  IContainer container = new Container(CreateContainerRules());<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  74. <PackageReference Include="MediatR" Version="12.2.0" />  
  75. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  76. <PackageReference Include="MediatR" Version="12.2.0" />  
  77. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  container.WithDependencyInjectionAdapter();<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  78. <PackageReference Include="MediatR" Version="12.2.0" />  
  79. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  80. <PackageReference Include="MediatR" Version="12.2.0" />  
  81. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return new DryIocContainerExtension(container);<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  82. <PackageReference Include="MediatR" Version="12.2.0" />  
  83. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  84. <PackageReference Include="MediatR" Version="12.2.0" />  
  85. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> protected override void RegisterRequiredTypes(IContainerRegistry containerRegistry)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  86. <PackageReference Include="MediatR" Version="12.2.0" />  
  87. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  88. <PackageReference Include="MediatR" Version="12.2.0" />  
  89. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  90. <PackageReference Include="MediatR" Version="12.2.0" />  
  91. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  base.RegisterRequiredTypes(containerRegistry);<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  92. <PackageReference Include="MediatR" Version="12.2.0" />  
  93. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  94. <PackageReference Include="MediatR" Version="12.2.0" />  
  95. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  IServiceCollection services = ConfigureServices();<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  96. <PackageReference Include="MediatR" Version="12.2.0" />  
  97. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  98. <PackageReference Include="MediatR" Version="12.2.0" />  
  99. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  IContainer container = ((IContainerExtension)containerRegistry).Instance;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  100. <PackageReference Include="MediatR" Version="12.2.0" />  
  101. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  102. <PackageReference Include="MediatR" Version="12.2.0" />  
  103. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  container.Populate(services);<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  104. <PackageReference Include="MediatR" Version="12.2.0" />  
  105. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  106. <PackageReference Include="MediatR" Version="12.2.0" />  
  107. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> private static ServiceCollection ConfigureServices()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  108. <PackageReference Include="MediatR" Version="12.2.0" />  
  109. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  110. <PackageReference Include="MediatR" Version="12.2.0" />  
  111. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  112. <PackageReference Include="MediatR" Version="12.2.0" />  
  113. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  var services = new ServiceCollection();<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  114. <PackageReference Include="MediatR" Version="12.2.0" />  
  115. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  116. <PackageReference Include="MediatR" Version="12.2.0" />  
  117. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  // 注入MediatR<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  118. <PackageReference Include="MediatR" Version="12.2.0" />  
  119. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  120. <PackageReference Include="MediatR" Version="12.2.0" />  
  121. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  var assemblies = AppDomain.CurrentDomain.GetAssemblies().ToList();<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  122. <PackageReference Include="MediatR" Version="12.2.0" />  
  123. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  124. <PackageReference Include="MediatR" Version="12.2.0" />  
  125. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  // 添加模块注入，未显示调用模块类型前，模块程序集是未加载到当出息序域`AppDomain.CurrentDomain`的<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  126. <PackageReference Include="MediatR" Version="12.2.0" />  
  127. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  128. <PackageReference Include="MediatR" Version="12.2.0" />  
  129. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  var assembly = typeof(SlugifyStringModule).GetAssembly();<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  130. <PackageReference Include="MediatR" Version="12.2.0" />  
  131. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  132. <PackageReference Include="MediatR" Version="12.2.0" />  
  133. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  assemblies.Add(assembly);<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  134. <PackageReference Include="MediatR" Version="12.2.0" />  
  135. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  136. <PackageReference Include="MediatR" Version="12.2.0" />  
  137. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  services.AddMediatR(configure =><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  138. <PackageReference Include="MediatR" Version="12.2.0" />  
  139. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  140. <PackageReference Include="MediatR" Version="12.2.0" />  
  141. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  142. <PackageReference Include="MediatR" Version="12.2.0" />  
  143. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  144. <PackageReference Include="MediatR" Version="12.2.0" />  
  145. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  146. <PackageReference Include="MediatR" Version="12.2.0" />  
  147. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  148. <PackageReference Include="MediatR" Version="12.2.0" />  
  149. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />configure.RegisterServicesFromAssemblies(assemblies.ToArray());<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  150. <PackageReference Include="MediatR" Version="12.2.0" />  
  151. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  152. <PackageReference Include="MediatR" Version="12.2.0" />  
  153. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  });<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  154. <PackageReference Include="MediatR" Version="12.2.0" />  
  155. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  156. <PackageReference Include="MediatR" Version="12.2.0" />  
  157. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return services;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  158. <PackageReference Include="MediatR" Version="12.2.0" />  
  159. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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在上面的代码中，我们重写了CreateContainerRules、CreateContainerExtension和RegisterRequiredTypes方法以配置DryIoc容器，并注册了MediatR服务和相关处置惩罚程序。
留意，在注册MediatR服务时，我们从当前已加载的程序集列表中查找并注册处置惩罚程序。如果模块是按需加载的，请确保在注册处置惩罚程序之前已加载了相应的模块。
此外，我们还演示了怎样手动添加模块程序集到列表中以便注册处置惩罚程序。这通常在你必要显式控制哪些模块和处置惩罚程序被注册时很有用。但是，请留意，在大多数情况下，你可能希望使用更自动化的方式来加载和注册模块及处置惩罚程序（例如，通过扫描特定目录或使用约定等）。这取决于你的具体需求和项目结构。
另外，请留意代码中的注释和说明，它们提供了有关每个步骤和配置的额外信息。在实际项目中，你可能必要根据项目的实际情况和需求进行相应的调整和优化。例如，你可能必要处置惩罚循环依赖、配置作用域、使用拦截器或装饰器等高级功能。这些都可以在DryIoc和MediatR的文档中找到更详细的说明和示例。
3. MediatR2种传递方式

有了前面的基础知识准备，我们添加类库工程CodeWF.Tools.MediatR.Notifications，并添加哀求界说（主工程及模块的相应处置惩罚程序必要实现）：
  1. public class TestRequest : IRequest{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public string? Args { get; set; }}
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添加通知界说：
  1. public class TestNotification : INotification{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public string? Args { get; set; }}
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哀求和通知界说结构一样（实现接口差别），只有一个字符串属性。
4. 添加处置惩罚程序

示例工程结构如下，因为该开源项目（文末链接）写在站长的AvaloniaUI桌面工具工程，本文只关注如下图3个工程即可：

在AvaloniaUI主工程(CodeWF.Tools.Desktop)添加哀求相应处置惩罚程序：
  1. public class TestHandler : IRequestHandler{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public async Task Handle(TestRequest request, CancellationToken cancellationToken)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return await Task.FromResult($"主工程处置惩罚程序：Args = {request.Args}, Now = {DateTime.Now}");<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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添加通知相应处置惩罚程序：
  1. public class TestNotificationHandler(INotificationService notificationService) : INotificationHandler{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public Task Handle(TestNotification notification, CancellationToken cancellationToken)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  notificationService.Show("Notification",<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  12. <PackageReference Include="MediatR" Version="12.2.0" />  
  13. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  14. <PackageReference Include="MediatR" Version="12.2.0" />  
  15. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  16. <PackageReference Include="MediatR" Version="12.2.0" />  
  17. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />$"主工程Notification处置惩罚程序：Args = {notification.Args}, Now = {DateTime.Now}");<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  18. <PackageReference Include="MediatR" Version="12.2.0" />  
  19. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  20. <PackageReference Include="MediatR" Version="12.2.0" />  
  21. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return Task.CompletedTask;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  22. <PackageReference Include="MediatR" Version="12.2.0" />  
  23. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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在模块【CodeWF.Tools.Modules.SlugifyString】中添加哀求相应处置惩罚程序(因为顺序关系，不会触发，这里添加只是演示哀求为一对一相应）：
  1. public class TestHandler : IRequestHandler{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public async Task Handle(TestRequest request, CancellationToken cancellationToken)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return await Task.FromResult($"模块【SlugifyString】Request处置惩罚程序：Args = {request.Args}, Now = {DateTime.Now}");<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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添加通知相应处置惩罚程序（会和主工程通知相应处置惩罚程序一样被触发）：
  1. public class TestNotificationHandler(INotificationService notificationService) : INotificationHandler{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public Task Handle(TestNotification notification, CancellationToken cancellationToken)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  notificationService.Show("Notification",<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  12. <PackageReference Include="MediatR" Version="12.2.0" />  
  13. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  14. <PackageReference Include="MediatR" Version="12.2.0" />  
  15. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  16. <PackageReference Include="MediatR" Version="12.2.0" />  
  17. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />$"模块【SlugifyString】Notification处置惩罚程序：Args = {notification.Args}, Now = {DateTime.Now}");<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  18. <PackageReference Include="MediatR" Version="12.2.0" />  
  19. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  20. <PackageReference Include="MediatR" Version="12.2.0" />  
  21. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  return Task.CompletedTask;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  22. <PackageReference Include="MediatR" Version="12.2.0" />  
  23. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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几个相应处置惩罚程序类界说类似：收到哀求时，返回格式化字符串；收到通知时，弹出提示表明当前是哪个位置收到的通知，便于演示效果。
5. 哀求和通知演示

触发利用我们写在模块【CodeWF.Tools.Modules.SlugifyString】中，在模块的ViewModel类里通过依赖注入获取哀求和通知的发送者实例ISender和IPublisher：
  1. using Unit = System.Reactive.Unit;namespace CodeWF.Tools.Modules.SlugifyString.ViewModels;public class SlugifyViewModel : ViewModelBase{<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  2. <PackageReference Include="MediatR" Version="12.2.0" />  
  3. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> // 省略别名转换相关逻辑代码，源码文末检察<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  4. <PackageReference Include="MediatR" Version="12.2.0" />  
  5. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  6. <PackageReference Include="MediatR" Version="12.2.0" />  
  7. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  private readonly INotificationService _notificationService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  8. <PackageReference Include="MediatR" Version="12.2.0" />  
  9. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> private readonly IClipboardService? _clipboardService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  10. <PackageReference Include="MediatR" Version="12.2.0" />  
  11. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> private readonly ITranslationService? _translationService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  12. <PackageReference Include="MediatR" Version="12.2.0" />  
  13. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public SlugifyViewModel(INotificationService notificationService, IClipboardService clipboardService,<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  14. <PackageReference Include="MediatR" Version="12.2.0" />  
  15. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  16. <PackageReference Include="MediatR" Version="12.2.0" />  
  17. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  ITranslationService translationService, ISender sender, IPublisher publisher) : base(sender, publisher)<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  18. <PackageReference Include="MediatR" Version="12.2.0" />  
  19. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  20. <PackageReference Include="MediatR" Version="12.2.0" />  
  21. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  22. <PackageReference Include="MediatR" Version="12.2.0" />  
  23. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  _notificationService = notificationService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  24. <PackageReference Include="MediatR" Version="12.2.0" />  
  25. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  26. <PackageReference Include="MediatR" Version="12.2.0" />  
  27. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  _clipboardService = clipboardService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  28. <PackageReference Include="MediatR" Version="12.2.0" />  
  29. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  30. <PackageReference Include="MediatR" Version="12.2.0" />  
  31. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  _translationService = translationService;<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  32. <PackageReference Include="MediatR" Version="12.2.0" />  
  33. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  34. <PackageReference Include="MediatR" Version="12.2.0" />  
  35. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  KindChanged = ReactiveCommand.Create(OnKindChanged);<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  36. <PackageReference Include="MediatR" Version="12.2.0" />  
  37. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  38. <PackageReference Include="MediatR" Version="12.2.0" />  
  39. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public async Task ExecuteMediatRRequestAsync()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  40. <PackageReference Include="MediatR" Version="12.2.0" />  
  41. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  42. <PackageReference Include="MediatR" Version="12.2.0" />  
  43. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  44. <PackageReference Include="MediatR" Version="12.2.0" />  
  45. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  var result = Sender.Send(new TestRequest() { Args = To });<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  46. <PackageReference Include="MediatR" Version="12.2.0" />  
  47. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  48. <PackageReference Include="MediatR" Version="12.2.0" />  
  49. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  _notificationService.Show("MediatR", $"收到相应：{result.Result}");<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  50. <PackageReference Include="MediatR" Version="12.2.0" />  
  51. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  52. <PackageReference Include="MediatR" Version="12.2.0" />  
  53. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> public async Task ExecuteMediatRNotificationAsync()<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  54. <PackageReference Include="MediatR" Version="12.2.0" />  
  55. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> {<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  56. <PackageReference Include="MediatR" Version="12.2.0" />  
  57. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /><PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  58. <PackageReference Include="MediatR" Version="12.2.0" />  
  59. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" />  await Publisher.Publish(new TestNotification() { Args = To });<PackageReference Include="Prism.DryIoc.Avalonia" Version="8.1.97.11072" />
  60. <PackageReference Include="MediatR" Version="12.2.0" />  
  61. <PackageReference Include="DryIoc.Microsoft.DependencyInjection" Version="8.0.0-preview-01" /> }}
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点击测试MediatR-Request按钮触发调用ISender.Send发出哀求并得到相应，通过点击测试MediatR-Notification按钮触发调用IPublisher.Publish发出通知。
哀求效果：

看上面的哀求效果：虽然在主工程和模块工程都注册了一个相应，但只有主工程被触发。
通知效果：

在主工程和模块工程都注册了一个通知相应，以是两个处置惩罚程序都弹出了提示。
6. 总结

为什么使用MediatR，而未使用Prism的事件聚合器？

站长开辟工具做了在线版(https://blazor.dotnet9.com)，也做了跨平台桌面版本（AvaloniaUI），两个版本使用MediatR可以复用大部门事件代码。
CQRS or DDD?

这节直接复制MediatR 在 .NET 应用中的实践 - 明志唯新 (yimingzhi.net)，大家应该可以学到些什么：
软件开辟发展到本日，模式和理念不断在架构中刷新：从分布式到微服务，再到云原生 ……。期间对一个程序员，尤其是服务端程序员，提出的要求越来越高。DDD（领域驱动设计）在微服务架构中一再被提及，甚至有人提出这是必须项！
实施一个完善的 DDD 还是有难度的，实际中奋战在一线的 CRUD 程序员还是不少。那么在 CRUD 和 DDD 之间我们是否还有缓冲区呢？MediatR 的作者曾经也撰文讨论过这个问题，我很认同他的基本观点：设计是为应用服务的，不能为了 DDD 而 DDD。
CQRS 的全称是："Command and Query Responsibility Segregation"，直译过来就是命令与查询责任分离，可以通俗的明白为 读写分离。

微软的官方文档中对此做过如下陈述：
CQRS 命令和查询责任分离数据存储的读取和更新利用分离的模式。 在应用程序中实现 CQRS 可以最大程度地提高其性能、可伸缩性和安全性。 通过迁移到 CQRS 而创建的机动性使系统能够随着时间的推移更好地发展，并防止更新命令在域级别导致合并冲突。
微软也给出了相应的隔离模子办理方案：
CQRS 使用命令来更新数据，使用查询来读取数据，将读取和写入 分离到差别的 模子中。

  • 命令应基于任务，而不是以数据为中央。
  • 命令可以放置在队列中进行异步处置惩罚，而不是同步处置惩罚。
  • 查询从不修改数据库。 查询返回的 DTO 不封装任何域知识。

CQRS 的好处包括：


  • 独立缩放: CQRS 答应读取和写入工作负载独立缩放，这可能会减少锁争用。
  • 优化的数据架构: 读取端可使用针对查询优化的架构，写入端可使用针对更新优化的架构。
  • 安全性: 更轻松地确保仅正确的域实体对数据执行写入利用。
  • 关注点分离: 分离读取和写入端可使模子更易维护且更机动。 大多数复杂的业务逻辑被分到写模子。 读模子会变得相对简单。
  • 查询更简单: 通过将具体化视图存储在读取数据库中，应用程序可在查询时避免复杂联接。
有了 MediatR 我们可以在应用中轻松实现 CQRS:

  • IRequest 的消息名称以 Command 为结尾的是命令，其对应的 Handler 执行写任务
  • IRequest 的消息名称以 Query 为结尾的是查询，其对应的 Handler 执行读数据
结束语

MediatR 是一个简单的中介者实现，可以极大降低我们的应用复杂度，也能够使得我们一路从 CRUD 到 CQRS 到 DDD 进行逐级演进。毕竟我们是生存在实际中的人，不能罔顾商业实际，纯粹一味寻求技能。

商业技能的演进，应该是一路连续的改革而不是来一场革命。疫情总有反复，但是我们得活着，相对轻松的活着！
参考

文中示例写了主要代码，但可能缺失部门细节，源码链接如下，欢迎留言互换。
参考文章：MediatR 在 .NET 应用中的实践
本文源码：Github

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