Declare Dependency Injection when the constructor takes a parameter.

huangapple
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英文:

Declare Dependency Injection when the constructor takes a paramter

问题

在.NET 6.0 Core控制台应用程序中学习DI：
我已经编写了这个：

  1. static void Main(string[] args)
  2. {
  3.     var serviceProvider = new ServiceCollection()
  4.         .AddSingleton<InterfaceOne, ClassOne>()
  5.         .AddSingleton<InterfaceTwo, ClassTwo>()
  6.         .BuildServiceProvider();
  7.     
  8.     var one = serviceProvider.GetRequiredService<InterfaceOne>(); // 可行。它的构造函数没有参数。
  9.     var two = serviceProvider.GetRequiredService<InterfaceTwo>(); // 不可行。它的构造函数有一个参数。
  11.     one.JustSayHi();
  12.     //two.SayWhateverMessageIsPassedToYou();
  13. }

ClassOne 实现了 InterfaceOne，它非常简单，在 constructor 中没有特殊的内容，所以我能够运行它。但是后来我创建了 ClassTwo 和 InterfaceTwo，但现在我不知道如何将参数传递给该类。这是我的 ClassTwo：

  1. public interface InterfaceTwo
  2. {
  3.     void SayWhateverMessageIsPassedToYou();
  4. }
  6. public class ClassTwo : InterfaceTwo
  7. {
  8.     private readonly string _sayThisThing;
  10.     public ClassTwo(string sayThisThing)
  11.     {
  12.         _sayThisThing = sayThisThing;
  13.     }
  15.     public void SayWhateverMessageIsPassedToYou()
  16.     {
  17.         Console.WriteLine(_sayThisThing);
  18.     }
  19. }
英文:

Learning DI in a .NET 6.0 Core Console Application:
I have written this:

  1.   static void Main(string[] args)
  2.     {
  3.         var serviceProvider = new ServiceCollection()
  4.             .AddSingleton&lt;InterfaceOne, ClassOne&gt;()
  5.             .AddSingleton&lt;InterfaceTwo, ClassTwo&gt;()
  6.             .BuildServiceProvider();
  7.         
  8.         var one = serviceProvider.GetRequiredService&lt;InterfaceOne&gt;(); // works. Its CTOR has no params.
  9.         var two = serviceProvider.GetRequiredService&lt;InterfaceTwo&gt;(); // does not work. Its CTOR has a param.
  11.         one.JustSayHi();
  12.         //two.SayWhateverMessageIsPassedToYou();
  13.     }

ClassOne implements InterfaceOne and it is super simple, nothing special in constructor so I was able to run that one. But then I created ClassTwo and InterfaceTwo but I don't know now how to pass my parameter to that class. Here is my ClassTwo :

  1. public interface InterfaceTwo
  2. {
  3.     void SayWhateverMessageIsPassedToYou();
  4. }
  6.     public class ClassTwo: InterfaceTwo
  7.     {
  8.         private readonly string _sayThisThing;
  10.         public ClassTwo(string sayThisThing)
  11.         {
  12.             _sayThisThing = sayThisThing;
  13.         }
  15.         public void SayWhateverMessageIsPassedToYou()
  16.         {
  17.             Console.WriteLine(_sayThisThing);
  18.         }
  19.     }

答案1

得分: 2

Brian的回答在详细说明了一些选项的同时，跳过了我认为最好的选项，如果可能的话：将您的代码重构以将服务与值分开。

例如，如果字符串值可能会随着应用程序的上下文而变化（例如，它作为请求参数提供），那么接口应该被更改为将字符串值作为方法参数：

  1. public interface InterfaceTwo
  2. {
  3.     void SayWhateverMessageIsPassedToYou(string sayThisThing);
  4. }

...然后，您的实现可以使用其构造函数来注入它所使用的服务。例如，注入控制台将使该类更容易在隔离的单元测试中进行测试：

  1. public class ClassTwo : InterfaceTwo
  2. {
  3.     TextWriter _output;
  4.     public ClassTwo(TextWriter output)
  5.     {
  6.         _output = output;
  7.     }
  8.     public void SayWhateverMessageIsPassedToYou(string sayThisThing)
  9.     {
  10.         _output.WriteLine(sayThisThing);
  11.     }
  12. }
  1. var serviceProvider = new ServiceCollection()
  2.     .AddSingleton<InterfaceTwo, ClassTwo>()
  3.     .AddSingleton<TextWriter>(Console.Out)
  4.     .BuildServiceProvider();

如果字符串不随上下文而变化，因此更改方法签名没有意义，考虑注入一个独立的服务，该服务充当该字符串的提供者，供您的类使用。

  1. public class ClassTwo : InterfaceTwo
  2. {
  3.     TextWriter _output;
  4.     IMessageProvider _messageProvider;
  5.     public ClassTwo(TextWriter output, IMessageProvider messageProvider)
  6.     {
  7.         _output = output;
  8.         _messageProvider = messageProvider;
  9.     }
  10.     public void SayWhateverMessageIsPassedToYou()
  11.     {
  12.         _output.WriteLine(_messageProvider.GetMessage());
  13.     }
  14. }
  16. public interface IMessageProvider
  17. {
  18.     string GetMessage();
  19. }
  21. public record FixedMessageProvider(string Message) : IMessageProvider
  22. {
  23.     public string GetMessage() => Message;
  24. }
  1. var serviceProvider = new ServiceCollection()
  2.     .AddSingleton<InterfaceTwo, ClassTwo>()
  3.     .AddSingleton<TextWriter>(Console.Out)
  4.     .AddSingleton<IMessageProvider>(new FixedMessageProvider("Hi"))
  5.     .BuildServiceProvider();

这是用于在ASP.NET Core中获取配置选项的模式示例：https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-7.0

英文:

While Brian's answer does a great job at spelling out some options, it skips the option which I would consider best of all, if it's possible: Refactor your code to separate Services from Values.

For example, if the string value might change with the context of your application (e.g. it's provided as a request parameter), then the interface should be changed to take the string value as a method parameter:

  1. public interface InterfaceTwo
  2. {
  3.     void SayWhateverMessageIsPassedToYou(string sayThisThing);
  4. }

... then your implementation could use its constructor to inject the services that it uses. For example, injecting the console would make the class easier to unit test in isolation:

  1. public class ClassTwo : InterfaceTwo
  2. {
  3.     TextWriter _output;
  4.     public ClassTwo(TextWriter output)
  5.     {
  6.         _output = output;
  7.     }
  8.     public void SayWhateverMessageIsPassedToYou(string sayThisThing)
  9.     {
  10.         _output.WriteLine(sayThisThing);
  11.     }
  12. }
  1. var serviceProvider = new ServiceCollection()
  2.     .AddSingleton&lt;InterfaceTwo, ClassTwo&gt;()
  3.     .AddSingleton&lt;TextWriter&gt;(Console.Out)
  4.     .BuildServiceProvider();

If the string doesn't change with context, so it doesn't make sense to change the method signature, consider injecting a separate service which acts as the provider of that string for your class to use.

  1. public class ClassTwo : InterfaceTwo
  2. {
  3.     TextWriter _output;
  4.     IMessageProvider _messageProvider;
  5.     public ClassTwo(TextWriter output, IMessageProvider messageProvider)
  6.     {
  7.         _output = output;
  8.         _messageProvider = messageProvider;
  9.     }
  10.     public void SayWhateverMessageIsPassedToYou()
  11.     {
  12.         _output.WriteLine(_messageProvider.GetMessage());
  13.     }
  14. }
  16. public interface IMessageProvider
  17. {
  18.     string GetMessage();
  19. }
  21. public record FixedMessageProvider(string Message) : IMessageProvider
  22. {
  23.     public string GetMessage() =&gt; Message;
  24. }
  1.     var serviceProvider = new ServiceCollection()
  2.         .AddSingleton&lt;InterfaceTwo, ClassTwo&gt;()
  3.         .AddSingleton&lt;TextWriter&gt;(Console.Out)
  4.         .AddSingleton&lt;IMessageProvider&gt;(new FixedMessageProvider(&quot;Hi&quot;))
  5.         .BuildServiceProvider();

This is the pattern used, for example, to get configuration options in ASP.NET Core: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-7.0

答案2

得分: 1

<h1>方法 1</h1>
为了直接回答您的问题，虽然我不建议这种方法：

  1. var serviceProvider = new ServiceCollection()
  2.     .AddSingleton&lt;InterfaceOne, ClassOne&gt;()
  3.     .AddSingleton&lt;InterfaceTwo, ClassTwo&gt;(sp =&gt; new ClassTwo(&quot;Hello, World!&quot;))
  4.     .BuildServiceProvider();

以下是完整上下文中的答案，附带了一个示例控制台应用程序...
https://github.com/CodeFontana/FoobarConsoleApp

FoobarConsoleUI.csproj

  1. &lt;Project Sdk=&quot;Microsoft.NET.Sdk&quot;&gt;
  3.   &lt;PropertyGroup&gt;
  4.     &lt;OutputType&gt;Exe&lt;/OutputType&gt;
  5.     &lt;TargetFramework&gt;net7.0&lt;/TargetFramework&gt;
  6.     &lt;ImplicitUsings&gt;enable&lt;/ImplicitUsings&gt;
  7.     &lt;Nullable&gt;enable&lt;/Nullable&gt;
  8.   &lt;/PropertyGroup&gt;
  10.   &lt;ItemGroup&gt;
  11.     &lt;PackageReference Include=&quot;Microsoft.Extensions.Hosting&quot; Version=&quot;7.0.1&quot; /&gt;
  12.     &lt;PackageReference Include=&quot;Microsoft.Extensions.Hosting.Abstractions&quot; Version=&quot;7.0.0&quot; /&gt;
  13.   &lt;/ItemGroup&gt;
  15. &lt;/Project&gt;

Program.cs

  1. using FoobarConsoleUI;
  2. using FoobarConsoleUI.Interfaces;
  3. using FoobarConsoleUI.Services;
  4. using Microsoft.Extensions.DependencyInjection;
  5. using Microsoft.Extensions.Hosting;
  6. using Microsoft.Extensions.Logging;
  8. HostApplicationBuilder builder = Host.CreateApplicationBuilder();
  10. builder.Services.AddTransient&lt;IFooService, FooService&gt;();
  11. builder.Services.AddTransient&lt;IBarService, BarService&gt;(sp =&gt;
  12. { 
  13.     ILogger&lt;BarService&gt; barLogger = sp.GetRequiredService&lt;ILogger&lt;BarService&gt;&gt;();
  14.     return new BarService(barLogger, &quot;Foobar&quot;);
  15. });
  16. builder.Services.AddHostedService&lt;App&gt;();
  18. IHost app = builder.Build();
  19. app.Run();

App.cs

  1. using FoobarConsoleUI.Interfaces;
  2. using Microsoft.Extensions.Configuration;
  3. using Microsoft.Extensions.Hosting;
  4. using Microsoft.Extensions.Logging;
  6. namespace FoobarConsoleUI;
  8. public class App : IHostedService
  9. {
  10.     private readonly IHostApplicationLifetime _hostApplicationLifetime;
  11.     private readonly IConfiguration _config;
  12.     private readonly ILogger&lt;App&gt; _logger;
  13.     private readonly IFooService _fooService;
  14.     private readonly IBarService _barService;
  16.     public App(IHostApplicationLifetime hostApplicationLifetime,
  17.                IConfiguration configuration,
  18.                ILogger&lt;App&gt; logger,
  19.                IFooService fooService,
  20.                IBarService barService)
  21.     {
  22.         _hostApplicationLifetime = hostApplicationLifetime;
  23.         _config = configuration;
  24.         _logger = logger;
  25.         _fooService = fooService;
  26.         _barService = barService;
  27.     }
  29.     public Task StartAsync(CancellationToken cancellationToken)
  30.     {
  31.         _hostApplicationLifetime.ApplicationStarted.Register(async () =&gt;
  32.         {
  33.             try
  34.             {
  35.                 await Task.Yield(); // https://github.com/dotnet/runtime/issues/36063
  36.                 await Task.Delay(1000); // Additional delay for Microsoft.Hosting.Lifetime messages
  37.                 Execute();
  38.             }
  39.             catch (Exception ex)
  40.             {
  41.                 _logger.LogError(ex, &quot;Unhandled exception!&quot;);
  42.             }
  43.             finally
  44.             {
  45.                 _hostApplicationLifetime.StopApplication();
  46.             }
  47.         });
  49.         return Task.CompletedTask;
  50.     }
  52.     public Task StopAsync(CancellationToken cancellationToken)
  53.     {
  54.         return Task.CompletedTask;
  55.     }
  57.     public void Execute()
  58.     {
  59.         _fooService.Foo();
  60.         _barService.Bar();
  61.     }
  62. }

IFooService:

  1. namespace FoobarConsoleUI.Interfaces;
  3. public interface IFooService
  4. {
  5.     void Foo();
  6. }

FooService

  1. using FoobarConsoleUI.Interfaces;
  2. using Microsoft.Extensions.Logging;
  4. namespace FoobarConsoleUI.Services;
  6. public class FooService : IFooService
  7. {
  8.     private readonly ILogger&lt;FooService&gt; _logger;
  10.     public FooService(ILogger&lt;FooService&gt; logger)
  11.     {
  12.         _logger = logger;
  13.     }
  15.     public void Foo()
  16.     {
  17.         _logger.LogInformation(&quot;Foo&quot;);
  18.     }
  19. }

IBarService:

  1. namespace FoobarConsoleUI.Interfaces;
  3. public interface IBarService
  4. {
  5.     void Bar();
  6. }

BarService:

  1. using FoobarConsoleUI.Interfaces;
  2. using Microsoft.Extensions.Logging;
  4. namespace FoobarConsoleUI.Services;
  6. public class BarService : IBarService
  7. {
  8.     private readonly ILogger&lt;BarService&gt; _logger;
  9.     private readonly string _inputText;
  11.     public BarService(ILogger&lt;BarService&gt; logger, 
  12.                       string inputText)
  13.     {
  14.         _logger = logger;
  15.         _inputText = inputText;
  16.     }
  18.     public void Bar()
  19.     {
  20.         _logger.LogInformation($&quot;Bar: {_inputText}&quot;);
  21.     }
  22. }

输出:
Declare Dependency Injection when the constructor takes a parameter.

<h1>方法 2</h1>
如评论中所讨论的，简单地不要求构造函数参数，而是使用属性。在这种方法中，在执行方法之前在运行时设置属性。这种方法的缺点是逻辑错误，即在设置属性之前调用SayWhateverMessageIsPassedToYou()方法。所以要小心。

我认为这种方法很简单，所以我不会提供代码示例。

<h1>方法 3</h1>
在某些情况下，您将不得不在运行时传递构造函数参数，这是您最终会遇到的情况。因此，最好的方法是实现一个工厂类，该类将被注入到您的DI中，并且在运行时可以使用正确的参数实例化您所需的类。

以下是从方法1中重新编写的相同程序，以使用工厂类...
Program.cs

  1. using FoobarFactoryConsoleUI;
  2. using FoobarFactoryConsoleUI.Factories;
  3. using FoobarFactoryConsoleUI.Interfaces;
  4. using FoobarFactoryConsoleUI.Services;
  5. using Microsoft.Extensions.DependencyInjection;
  6. using Microsoft.Extensions.Hosting;
  7. using Microsoft.Extensions.Logging;
  9. HostApplicationBuilder builder = Host.CreateApplicationBuilder();
  11. builder.Services.AddTransient&lt;IFooService, FooService&gt;();
  12. builder.Services.AddTransient&lt;BarServiceFactory&gt;();
  13. builder.Services.AddHostedService&lt;App&gt;();
  15. IHost app = builder.Build();
  16. app.Run();

App.cs

  1. using FoobarFactoryConsoleUI.Factories;
  2. using FoobarFactoryConsoleUI.Interfaces;
  3. using Microsoft.Extensions.Configuration;
  4. using Microsoft.Extensions.Hosting;
  5. using Microsoft.Extensions.Logging;
  7. namespace FoobarFactoryConsoleUI;
  8. public class App
  10. <details>
  11. <summary>英文:</summary>
  13. &lt;h1&gt;Method 1&lt;/h1&gt;
  14. To most directly answer your question, though I would discourage this approach:

var serviceProvider = new ServiceCollection()
.AddSingleton<InterfaceOne, ClassOne>()
.AddSingleton<InterfaceTwo, ClassTwo>(sp => new ClassTwo("Hello, World!"))
.BuildServiceProvider();

  2. Here&#39;s the answer in full context with a sample console app...  
  3. https://github.com/CodeFontana/FoobarConsoleApp
  5. FoobarConsoleUI.csproj

<Project Sdk="Microsoft.NET.Sdk">

<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net7.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
</PropertyGroup>

<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.1" />
<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="7.0.0" />
</ItemGroup>

</Project>

  2. Program.cs

using FoobarConsoleUI;
using FoobarConsoleUI.Interfaces;
using FoobarConsoleUI.Services;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

HostApplicationBuilder builder = Host.CreateApplicationBuilder();

builder.Services.AddTransient<IFooService, FooService>();
builder.Services.AddTransient<IBarService, BarService>(sp =>
{
ILogger<BarService> barLogger = sp.GetRequiredService<ILogger<BarService>>();
return new BarService(barLogger, "Foobar");
});
builder.Services.AddHostedService<App>();

IHost app = builder.Build();
app.Run();

  2. App.cs

using FoobarConsoleUI.Interfaces;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace FoobarConsoleUI;

public class App : IHostedService
{
private readonly IHostApplicationLifetime _hostApplicationLifetime;
private readonly IConfiguration _config;
private readonly ILogger<App> _logger;
private readonly IFooService _fooService;
private readonly IBarService _barService;

  1. public App(IHostApplicationLifetime hostApplicationLifetime,
  2.            IConfiguration configuration,
  3.            ILogger&lt;App&gt; logger,
  4.            IFooService fooService,
  5.            IBarService barService)
  6. {
  7.     _hostApplicationLifetime = hostApplicationLifetime;
  8.     _config = configuration;
  9.     _logger = logger;
  10.     _fooService = fooService;
  11.     _barService = barService;
  12. }
  14. public Task StartAsync(CancellationToken cancellationToken)
  15. {
  16.     _hostApplicationLifetime.ApplicationStarted.Register(async () =&gt;
  17.     {
  18.         try
  19.         {
  20.             await Task.Yield(); // https://github.com/dotnet/runtime/issues/36063
  21.             await Task.Delay(1000); // Additional delay for Microsoft.Hosting.Lifetime messages
  22.             Execute();
  23.         }
  24.         catch (Exception ex)
  25.         {
  26.             _logger.LogError(ex, &quot;Unhandled exception!&quot;);
  27.         }
  28.         finally
  29.         {
  30.             _hostApplicationLifetime.StopApplication();
  31.         }
  32.     });
  34.     return Task.CompletedTask;
  35. }
  37. public Task StopAsync(CancellationToken cancellationToken)
  38. {
  39.     return Task.CompletedTask;
  40. }
  42. public void Execute()
  43. {
  44.     _fooService.Foo();
  45.     _barService.Bar();
  46. }

}

  2. IFooService:

namespace FoobarConsoleUI.Interfaces;

public interface IFooService
{
void Foo();
}

  2. FooService

using FoobarConsoleUI.Interfaces;
using Microsoft.Extensions.Logging;

namespace FoobarConsoleUI.Services;

public class FooService : IFooService
{
private readonly ILogger<FooService> _logger;

  1. public FooService(ILogger&lt;FooService&gt; logger)
  2. {
  3.     _logger = logger;
  4. }
  6. public void Foo()
  7. {
  8.     _logger.LogInformation(&quot;Foo&quot;);
  9. }

}

  2. IBarService:

namespace FoobarConsoleUI.Interfaces;

public interface IBarService
{
void Bar();
}

  2. BarService:

using FoobarConsoleUI.Interfaces;
using Microsoft.Extensions.Logging;

namespace FoobarConsoleUI.Services;

public class BarService : IBarService
{
private readonly ILogger<BarService> _logger;
private readonly string _inputText;

  1. public BarService(ILogger&lt;BarService&gt; logger, 
  2.                   string inputText)
  3. {
  4.     _logger = logger;
  5.     _inputText = inputText;
  6. }
  8. public void Bar()
  9. {
  10.     _logger.LogInformation($&quot;Bar: {_inputText}&quot;);
  11. }

}

  2. Output:
  3. [![enter image description here][1]][1]
  5.   [1]: https://i.stack.imgur.com/bmbmG.png
  7. &lt;h1&gt;Method 2&lt;/h1&gt;
  8. As discussed in the comments, simply don&#39;t require the constructor parameter, and use a property instead.  In this approach, the property is passed at runtime before executing your method.
  10. The downside to this approach is a logic error, where you call your SayWhateverMessageIsPassedToYou() before your property is set. So be careful.
  12. I think this approach is straightforward, so I won&#39;t provide a code sample.
  14. &lt;h1&gt;Method 3&lt;/h1&gt;
  15. In the scenario, which you will run into eventually, sometimes you just have to pass a constructor parameter at runtime.  Thus the best approach is to implement a factory class, which would get injected into your DI, and at runtime can instantiate your required class with the proper parameters.  
  16.   
  17. Here&#39;s the same program from Method 1, rewritten to use a factory class...
  19. Program.cs

using FoobarFactoryConsoleUI;
using FoobarFactoryConsoleUI.Factories;
using FoobarFactoryConsoleUI.Interfaces;
using FoobarFactoryConsoleUI.Services;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

HostApplicationBuilder builder = Host.CreateApplicationBuilder();

builder.Services.AddTransient<IFooService, FooService>();
builder.Services.AddTransient<BarServiceFactory>();
builder.Services.AddHostedService<App>();

IHost app = builder.Build();
app.Run();

  2. App.cs

using FoobarFactoryConsoleUI.Factories;
using FoobarFactoryConsoleUI.Interfaces;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace FoobarFactoryConsoleUI;
public class App : IHostedService
{
private readonly IHostApplicationLifetime _hostApplicationLifetime;
private readonly IConfiguration _config;
private readonly ILogger<App> _logger;
private readonly IFooService _fooService;
private readonly BarServiceFactory _barFactory;

  1. public App(IHostApplicationLifetime hostApplicationLifetime,
  2.            IConfiguration configuration,
  3.            ILogger&lt;App&gt; logger,
  4.            IFooService fooService,
  5.            BarServiceFactory barFactory)
  6. {
  7.     _hostApplicationLifetime = hostApplicationLifetime;
  8.     _config = configuration;
  9.     _logger = logger;
  10.     _fooService = fooService;
  11.     _barFactory = barFactory;
  12. }
  14. public Task StartAsync(CancellationToken cancellationToken)
  15. {
  16.     _hostApplicationLifetime.ApplicationStarted.Register(async () =&gt;
  17.     {
  18.         try
  19.         {
  20.             await Task.Yield(); // https://github.com/dotnet/runtime/issues/36063
  21.             await Task.Delay(1000); // Additional delay for Microsoft.Hosting.Lifetime messages
  22.             Execute();
  23.         }
  24.         catch (Exception ex)
  25.         {
  26.             _logger.LogError(ex, &quot;Unhandled exception!&quot;);
  27.         }
  28.         finally
  29.         {
  30.             _hostApplicationLifetime.StopApplication();
  31.         }
  32.     });
  34.     return Task.CompletedTask;
  35. }
  37. public Task StopAsync(CancellationToken cancellationToken)
  38. {
  39.     return Task.CompletedTask;
  40. }
  42. public void Execute()
  43. {
  44.     _fooService.Foo();
  45.     IBarService barService = _barFactory.CreateInstance(&quot;Hello, World!&quot;);
  46.     barService.Bar();
  47. }

}

  2. BarServiceFactory.cs

using FoobarFactoryConsoleUI.Interfaces;
using FoobarFactoryConsoleUI.Services;
using Microsoft.Extensions.Logging;

namespace FoobarFactoryConsoleUI.Factories;

public class BarServiceFactory
{
private readonly ILoggerFactory _loggerFactory;

  1. public BarServiceFactory(ILoggerFactory loggerFactory)
  2. {
  3.     _loggerFactory = loggerFactory;
  4. }
  6. public IBarService CreateInstance(string inputText)
  7. {
  8.     ILogger&lt;BarService&gt; _barLogger = _loggerFactory.CreateLogger&lt;BarService&gt;();
  9.     return new BarService(_barLogger, inputText);
  10. }

}

  2. The rest of the code is exactly the same as Method 1 above.
  4. </details>

huangapple
  • 本文由 发表于 2023年5月18日 02:21:43
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  • .net-core
  • c#
  • dependency-injection
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