我在.NET Core Worker服务中遇到了一些依赖注入问题,请看下面的代码。Program.cs
文件。
public static void Main(string[] args)
{
Log.Logger = new LoggerConfiguration()
.MinimumLevel.Debug()
.MinimumLevel.Override("Microsof)t", LogEventLevel.Warning)
.Enrich.FromLogContext()
.WriteTo.File(@"C:\MyApp_Log\Log.txt")
.CreateLogger();
try
{
Log.Information("Starting up the service.");
CreateHostBuilder(args).Build().Run();
return;
}
catch (Exception ex)
{
Log.Fatal(ex, "There was a problem starting the service");
return;
}
finally
{
Log.CloseAndFlush();
}
}
public static IHostBuilder CreateHostBuilder(string[] args)
{
return Host.CreateDefaultBuilder(args)
.UseWindowsService()
.ConfigureServices((hostContext, services) =>
{
services.AddScoped<IMyAppCoreService, MyAppCoreService>();
services.AddDbContext<MyAppCSContext>(options => options.UseSqlServer("Data Source=xx.xxx.xx.xxx;Database=Mydb;User ID = sa;Password=mypassword"));
services.AddHostedService<Worker>();
})
.UseSerilog();
}
请看下面的代码 Worker.cs
档案
private readonly ILogger<Worker> _logger;
private readonly IMyAppCoreService _CoreService;
public Worker(ILogger<Worker> logger, IMyAppCoreService CoreService)
{
_logger = logger;
_CoreService = CoreService;
}
public override Task StartAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("The MyApp_CoreService has been Started...");
return base.StartAsync(cancellationToken);
}
public override Task StopAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("The MyApp_CoreService has been stopped...");
return base.StopAsync(cancellationToken);
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
_CoreService.CheckAndProcessResult();
await Task.Delay(1000, stoppingToken);
}
}
当我运行上述查询时,我得到了以下查询。
验证服务描述符时出错
服务类型。MyApp.CS.Business.Facade.IMyAppCoreService Lifetime: Scoped ImplementationType.ImplementationType: MyApp.CS.Business.Services.Facade.IMyAppCoreService MyApp.CS.Business.Services.MyAppCoreService"。在尝试激活 "MyApp.CS.Business.Services.MyAppCoreService "时,无法解析'MyApp.CS.Data.Facade.ICommonRepository'类型的服务。
请您告诉我,我哪里做错了?
EDIT: 当我把所有的接口都注册到它的类中后,我得到了新的错误,如下所示。
在验证服务描述符 "ServiceType.Hosting.Implement "时出错。Microsoft.Extensions.HostedService Lifetime: Singleton ImplementationType.MyApp_CoreService.Worker.IHostedService MyApp_CoreService.Worker'。不能从单人'Microsoft.Extensions.HostedService'中消耗作用域服务'MyApp.CS.Business.Facade.IMyAppCoreService'。
你注入了Serivce IMyAppCoreService
为 "范围"。范围内的服务只能由 ScopedServiceProvider
.
我的第一个猜测是,你并不是故意的--你的意思是将你的服务注入为Singleton。
services.AddSingleton<IMyAppCoreService, MyAppCoreService>();
但这可能行不通,因为你使用的是EF Core,它将Context-like类注入为scoped。你有两个选择。
services.AddDbContext<YourContext>(opts => { ...config...}, ServiceLifetime.Transient);
有一个... IServiceProvider
属性,称为ServiceProvider注入到 Worker
而是 的服务。
在ExecuteAsync-Loop中,这将整齐地处理每个Loop的EFCore-Data Context对象,在我看来是最干净的选择。
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
using (var scope = ServiceProvider.CreateScope())
{
scope.ServiceProvider.GetRequiredService<IMyAppCoreService>().CheckAndProcessResult();
}
await Task.Delay(1000, stoppingToken);
这将整齐地处理每个Loop的EFCore -Data Context对象,在我看来是最干净的选择。