我知道在这个问题上互联网上有很多问题和信息。但是搜索4-5个小时，我无法解决问题。寻找直接或间接的帮助/指导。
我正在使用：VS 2017 ASP .Net Core 2.0
说，我在解决方案中有3个项目。
在我的Api中，来自CustomExceptionFilter的{{1}}。我正在处理来自IExceptionFilter的所有异常。
我需要在OnException()内创建日志。要记录，我需要访问DB。
为此目的，在OnException，Startup.cs中，我注入了ConfigureServices()的依赖关系，因为它需要CustomExceptionFilter方法中的LoggingWrapper。
以下是代码：
OnException()此处services.AddSingleton<IExceptionFilter>(
new CustomExceptionFilter(
new LogDataAccess(
appServiceConfig.ConnectionString, appServiceConfig.Database)));
是将日志插入数据库的类。
我已经覆盖了LogDataAccess类中的构造函数，如：
CustomExceptionFilter构建项目很好。我跑的时候，到目前为止，private ILogDataAccess logDataAccess;
public CustomExceptionFilter(ILogDataAccess logDataAccess)
{
this.logDataAccess = logDataAccess;
}
执行得很好。 startup.cs很好地实例化了。在Startup.cs中完成其他语句之后，当它试图从“logDataAccess”的主入口点出来时，
它显示错误：
这是错误的堆栈跟踪。
program.cs我在同一方法 System.InvalidOperationException: Unable to resolve service for type 'DataAccess.ILogDataAccess' while attempting to activate 'QuestionService.Common.CustomExceptionFilter'.
at Microsoft.Extensions.Internal.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)
at lambda_method(Closure , IServiceProvider , Object[] )
at Microsoft.AspNetCore.Mvc.TypeFilterAttribute.CreateInstance(IServiceProvider serviceProvider)
at Microsoft.AspNetCore.Mvc.Internal.DefaultFilterProvider.ProvideFilter(FilterProviderContext context, FilterItem filterItem)
at Microsoft.AspNetCore.Mvc.Internal.DefaultFilterProvider.OnProvidersExecuting(FilterProviderContext context)
at Microsoft.AspNetCore.Mvc.Internal.FilterFactory.CreateUncachedFiltersCore(IFilterProvider[] filterProviders, ActionContext actionContext, List`1 filterItems)
at Microsoft.AspNetCore.Mvc.Internal.FilterFactory.GetAllFilters(IFilterProvider[] filterProviders, ActionContext actionContext)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvokerCache.GetCachedResult(ControllerContext controllerContext)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvokerProvider.OnProvidersExecuting(ActionInvokerProviderContext context)
at Microsoft.AspNetCore.Mvc.Internal.ActionInvokerFactory.CreateInvoker(ActionContext actionContext)
at Microsoft.AspNetCore.Mvc.Internal.MvcAttributeRouteHandler.<>c__DisplayClass12_0.<RouteAsync>b__0(HttpContext c)
at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.<Invoke>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.<Invoke>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()
中添加了CustomExceptionFilter
也是这样。
ConfigureServices()这是为全局异常过滤器添加的。
答案 0 :(得分：0)
您需要在DI中注册LogDataAccess而不是CustomExceptionFilter。
变化：
services.AddSingleton<IExceptionFilter>(new CustomExceptionFilter(new LogDataAccess(
appServiceConfig.ConnectionString, appServiceConfig.Database)));
为：
services.AddSingleton<ILogDataAccess>(new LogDataAccess(
appServiceConfig.ConnectionString, appServiceConfig.Database));