无法将SignalR IHubContext注入类

问题描述

我是使用SignalR的新手，在尝试将IHubContext注入类时遇到了麻烦。尝试运行代码时，出现如下所示的异常。我尝试在startup.cs中注入TimerEventHandler的行上出错，这是代码：

public class TimerEventHandler : ITimerEventHandler
    {
        private readonly IConfiguration _config;
        private readonly IHubContext<IndexHub> _hubContext;
    
        public TimerEventHandler(IHubContext<IndexHub> hubContext,IConfiguration config)
        {
            _hubContext = hubContext;
            _config = config;            
        }
    }
  

ITimerEventHandler

public interface ITimerEventHandler
{
    Task OnTimedEvent(object source,ElapsedEventArgs e,string connectionId);
}

这是我Startup.cs中的代码

public void ConfigureServices(IServiceCollection services)
{            
   services.AddSignalR(o =>
   {
      o.EnableDetailedErrors = true;
   });
   services.AddScoped<ITimerEventHandler,TimerEventHandler>();            
}

来自indexhub的代码

public class IndexHub : Hub
{       

    private readonly IServiceBusHelper _serviceBusHelper;
    private readonly ITimerEventHandler _timerEventHandler;
    

    public IndexHub(IServiceBusHelper serviceBusHelper,ITimerEventHandler timerEventHandler)
    {
        _serviceBusHelper = serviceBusHelper;
        _timerEventHandler = timerEventHandler;
    }
    ....

}

Program.cs

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

我得到的例外是：

> System.AggregateException
  HResult=0x80131500
  Message=Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: my.portal.Hubs.ITimerEventHandler Lifetime: Scoped ImplementationType: my.portal.Hubs.TimerEventHandler': Unable to resolve service for type 'Microsoft.AspNet.SignalR.IHubContext`1[my.portal.Hubs.IndexHub]' while attempting to activate 'my.portal.Hubs.TimerEventHandler'.)
  Source=Microsoft.Extensions.DependencyInjection
  StackTrace:
   at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable`1 serviceDescriptors,ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services,ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.DefaultServiceProviderFactory.CreateServiceProvider(IServiceCollection containerBuilder)
   at Microsoft.Extensions.Hosting.Internal.ServiceFactoryAdapter`1.CreateServiceProvider(Object containerBuilder)
   at Microsoft.Extensions.Hosting.HostBuilder.CreateServiceProvider()
   at Microsoft.Extensions.Hosting.HostBuilder.Build()
   at my.portal.Program.Main(String[] args) in Program.cs:line 10

你们中的任何专家都可以帮忙吗？

解决方法

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