.NET 7项目中ILogger无法注入的问题及解决咨询

问题场景 #

原本日志功能正常的.NET 7 Core项目，在AccountController中注入日志时抛出解析异常。

控制器代码 #

public class AccountController : ControllerBase
{
    private readonly IConfiguration? _configuration;
    private readonly ILogger<AccountController>? _logger;

    public AccountController(IConfiguration? configuration, ILogger? logger)
    {
        _configuration = configuration;
        _logger = (ILogger<AccountController>?)logger;
    }
}

抛出异常 #

System.InvalidOperationException: Unable to resolve service for type
'Microsoft.Extensions.Logging.ILogger' while attempting to activate
'Modules.Authenticate.Core.Controllers.Api.AccountController'. at
Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider
sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)

at lambda_method9(Closure, IServiceProvider, Object[]) at
Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass6_0.g__CreateController|0(ControllerContext
controllerContext) at
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State&
next, Scope& scope, Object& state, Boolean& isCompleted) at
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|20_0(ResourceInvoker
invoker, Task lastTask, State next, Scope scope, Object state, Boolean
isCompleted) at
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker
invoker, Task task, IDisposable scope) at
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker
invoker, Task task, IDisposable scope) at
Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint
endpoint, Task requestTask, ILogger logger) at
Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext
httpContext) at
Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext
httpContext, ISwaggerProvider swaggerProvider) at
Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext
context) at
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext
context) at
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext
context)

解决方法 #

核心原因 #

.NET Core默认依赖注入容器中，仅自动注册泛型版本的ILogger<T>，非泛型的ILogger并未被默认添加到服务容器，因此无法被解析。

修正代码 #

将构造函数中的参数类型改为泛型的ILogger<AccountController>，同时移除不必要的强制转换：

public class AccountController : ControllerBase
{
    private readonly IConfiguration? _configuration;
    private readonly ILogger<AccountController>? _logger;

    public AccountController(IConfiguration? configuration, ILogger<AccountController>? logger)
    {
        _configuration = configuration;
        _logger = logger;
    }
}

额外说明 #

• 如果项目启用了nullable引用类型，?可以保留；若确保注入不会为null，也可直接移除?。
• 无需手动注册ILogger<T>，.NET Core模板默认已通过WebApplication.CreateBuilder自动配置日志服务。

内容的提问来源于stack exchange，提问作者jstuardo