我有一个从默认的。NET核心模板创建的辅助服务。我有两个额外的服务我想运行，一个发出事件，另一个使用它。因此，理想情况下，它们都应该被注入到单个worker托管服务中。我怎么才能让这一切发生？我尝试了如下代码，但我得到了:System.InvalidOperationException:“在尝试激活”MessageQueueReceiver.Worker“时，无法解析类型”Receiver.IMessageReceiver“的服务。”
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) =>
{
services.AddSingleton<IMessageReceiver, MessageReceiver>();
services.AddSingleton<IWebhookMessageForwarder, WebhookMessageForwarder>();
services.AddHostedService<Worker>();
});
}
public class Worker : BackgroundService
{
private readonly ILogger _logger;
private readonly IMessageReceiver _messageReceiver;
private readonly IWebhookMessageForwarder _forwarder;
public Worker(ILogger<Worker> logger,
IMessageReceiver messageReceiver,
IWebhookMessageForwarder forwarder)
{
_logger = logger;
_messageReceiver = messageReceiver;
_forwarder = forwarder;
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
_messageReceiver.MessageReceived += _forwarder.OnMessageReceived;
_messageReceiver.RegisterHandlerAndReceiveMessages();
while (!stoppingToken.IsCancellationRequested)
{
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
await Task.Delay(TimeSpan.FromSeconds(60), stoppingToken);
}
}
}
问题似乎是在初始化您的某个类。请检查Worker，Message Receiver和MessageForwarder类的constructor。
同样检查这一行，您正在创建接口的实例。
services.AddSingleton<IWebhookMessageForwarder, IWebhookMessageForwarder>()
我尝试了下面的代码，它工作了，它承载了一个BackgroundService。
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) =>
{
services.AddSingleton<IMessageReceiver, MessageReceiver>();
services.AddSingleton<IWebhookMessageForwarder, WebhookMessageForwarder>();
services.AddHostedService<Worker>();
});
}
public class Worker : BackgroundService
{
private readonly ILogger<Worker> _logger;
private readonly IMessageReceiver _messageReceiver;
private readonly IWebhookMessageForwarder _forwarder;
public Worker(IMessageReceiver messageReceiver,
IWebhookMessageForwarder forwarder)
{
_messageReceiver = messageReceiver;
_forwarder = forwarder;
}
public override Task StartAsync(CancellationToken cancellationToken)
{
return base.StartAsync(cancellationToken);
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
System.Console.WriteLine("Hello");
await Task.Delay(TimeSpan.FromSeconds(60), stoppingToken);
}
}
}
public interface IWebhookMessageForwarder
{
}
public class WebhookMessageForwarder : IWebhookMessageForwarder
{
}
public interface IMessageReceiver
{
}
public class MessageReceiver : IMessageReceiver
{
}
