Unity 4.0.0与.NET4.8下Microsoft Logger注册及依赖解析失败求助

环境与报错 #

使用Unity 4.0.0 + .NET 4.8，项目抛出错误：

Resolution of the dependency failed, type = "Test.IWorker", name = "(none)"

Worker类代码：

public class SimpleWorker : IWorker
{
    private readonly ILogger _logger;
    public SimpleWorker(ILogger<SimpleWorker> logger)
    {
        _logger = logger;
    }
}

已尝试的无效方案 #

• 反射调用LoggerFactory扩展方法注册：

_container = new UnityContainer();
var loggerFactory = new LoggerFactory();
var factoryMethod =
    typeof(LoggerFactoryExtensions).
        GetMethods(BindingFlags.Static | BindingFlags.Public)
        .First(x => x.ContainsGenericParameters);

_container.RegisterType(typeof(ILogger<>), new InjectionFactory((c, t, s) =>
{
    var genFactoryMethod =
        factoryMethod.MakeGenericMethod(t.GetGenericArguments()[0]);
    return genFactoryMethod.Invoke(null, new object[] { loggerFactory });
}));

• 直接注册具体ILogger类型：

_container = new UnityContainer();
_container.RegisterType<ILogger<SimpleWorker>>();

补充问题：LoggerFactory注册后的新报错 #

尝试以下注册代码后：

var factory = new LoggerFactory();
factory.AddLog4Net("log4net.config");
container.RegisterInstance<ILoggerFactory>(factory);
container.RegisterType(typeof(ILogger<>), typeof(Logger<>));

执行容器解析遍历代码时抛出错误：

Resolving Microsoft.Extensions.Logging.ILogger`1[TCategoryName][],(none)
---> System.InvalidOperationException: Could not execute the method because either the method itself or the containing type is not fully instantiated.

解决方案 #

1. 正确注册ILogger<>的方式 #

Unity 4.x对泛型类型的注册需要明确关联工厂逻辑，修正后的注册代码可确保依赖正常解析：

var container = new UnityContainer();
// 初始化LoggerFactory并配置log4net
var loggerFactory = new LoggerFactory();
loggerFactory.AddLog4Net("log4net.config");
// 将LoggerFactory注册为容器单例
container.RegisterInstance<ILoggerFactory>(loggerFactory, new ContainerControlledLifetimeManager());
// 为泛型ILogger<>绑定创建逻辑，通过LoggerFactory生成具体实例
container.RegisterType(typeof(ILogger<>), new InjectionFactory((container, type, name) =>
{
    var categoryType = type.GetGenericArguments()[0];
    return container.Resolve<ILoggerFactory>().CreateLogger(categoryType);
}));
// 注册Worker实现
container.RegisterType<IWorker, SimpleWorker>();

2. 解决ResolveAll引发的错误 #

ResolveAll会尝试解析开放泛型类型（如ILogger<>），但未闭合的泛型无法实例化，需在遍历中跳过这类类型：

foreach (var item in _unityContainer.Registrations)
{
    // 跳过开放泛型定义，避免无效解析
    if (item.RegisteredType.IsGenericTypeDefinition)
        continue;
        
    var named = _unityContainer.ResolveAll(item.RegisteredType);
    if (_unityContainer.IsRegistered(item.RegisteredType))
    {
        var tmp = _unityContainer.Resolve(item.RegisteredType);
    }
}

内容的提问来源于stack exchange，提问作者pakerinjo