解决通用Microsoft.Extensions.Logging.ILogger 使用Unity - 获取InvalidCastException

Question

我试图在Unity（版本4）中注册一个通用的ILogger（来自Microsoft.Extensions.Logging，而不是来自Serilog）。

我有以下课程：

public class MyClass
{
    private readonly Microsoft.Extensions.Logging.ILogger<MyClass> _logger;

    public MyClass(Microsoft.Extensions.Logging.ILogger<MyClass> logger)
    {
        _logger = logger;
    }
}

以下Unity注册和测试：

// Arrange
IUnityContainer container = new UnityContainer();

// provider from Serilog.Extensions.Logging nuget package
var provider = new Serilog.Extensions.Logging.SerilogLoggerProvider();

container.RegisterType(typeof(Microsoft.Extensions.Logging.ILogger<>),
    new InjectionFactory((ctr, type, name) =>
    {
        var loggerType = type.GetGenericArguments()[0].FullName;
        Microsoft.Extensions.Logging.ILogger logger = provider.CreateLogger(loggerType);
        return logger;
    }));

container.RegisterType<MyClass, MyClass>(); // just for demo purpose. 

// Assert
container.Resolve<MyClass>();

这对我来说似乎没关系，太糟糕了我在解决时遇到以下错误：

例外情况是：InvalidCastException - 无法将类型为“Serilog.Extensions.Logging.SerilogLogger”的对象强制转换为“Microsoft.Extensions.Logging.ILogger`1 [MyNamespace.MyClass]”。

如何解决这个问题？

完全例外：

Microsoft.Practices.Unity.ResolutionFailedException：依赖项的解析失败，type =“MyNamespace.MyClass”，name =“（none）”。发生异常时：解析构造函数MyNamespace.MyClass的参数“logger”（Microsoft.Extensions.Logging.ILogger

1[[MyNamespace.MyClass, MyNamespace.Infra.UnitTests, Version=1.0.0.0, Culture=neutral, PublicKeyToken=edbaf8e9a324553f]] logger).
  Exception is: InvalidCastException - Unable to cast object of type 'Serilog.Extensions.Logging.SerilogLogger' to type 'Microsoft.Extensions.Logging.ILogger

1 [MyNamespace.MyClass]'。

更新

使用Microsoft.Extensions.DependencyInjection时，这适用：

// Arrange
var serviceCollection = new Microsoft.Extensions.DependencyInjection.ServiceCollection()
    .AddLogging(builder => builder.AddSerilog())
    .AddTransient<MyClass, MyClass>();

var serviceProvider = serviceCollection.BuildServiceProvider();

// Assert
serviceProvider.GetService<MyClass>();

所以我尝试使用Unity而不是Microsoft.Extensions.DependencyInjection

不幸的是，Unity没有AddSerilog，我必然会选择Unity

Answer 1

我在MakeGenericMethod和帮助方法的帮助下解决了这个问题：

private static ILogger<T> CreateLogger<T>(ILoggerFactory factory)
{
    return new Logger<T>(factory);
}

最后的代码（没有反射缓存等）：

// Arrange
IUnityContainer container = new UnityContainer();

var logfactory = new LoggerFactory();

var provider = new Serilog.Extensions.Logging.SerilogLoggerProvider();
logfactory.AddProvider(provider);

container.RegisterType(typeof(Microsoft.Extensions.Logging.ILogger<>),
    new InjectionFactory((ctr, type, name) =>
    {
        var loggerType = type.GetGenericArguments()[0];

        var myType = this.GetType();

        var createLoggerMethod1 = myType.GetMethod(nameof(CreateLogger),BindingFlags.Static | BindingFlags.NonPublic);

        var createLoggerMethod = createLoggerMethod1.MakeGenericMethod(loggerType);

        var logger = createLoggerMethod.Invoke(this, new object[] {logfactory});

        return logger;
    }));

container.RegisterType<MyClass, MyClass>();

// Assert
container.Resolve<MyClass>();