Using a scoped service inside a HostedService

When trying to resolve a scoped dependency inside a HostedService, the runtime returned the following error message:

System.InvalidOperationException: Cannot consume scoped service ‘IScoped’ from singleton ‘Microsoft.Extensions.Hosting.IHostedService’.

The problem is that the IHostedService is a singleton and is created outside a dependency injection scope. Trying to inject any scoped service(e.g.  an EF Core DbContext) will result in the error message above.

To solve this problem you have to create a dependency injection scope using the IServiceScopeFactory. Within this scope you can use the scoped services:

	public class Worker : BackgroundService
	{
	private readonly ILogger<Worker> _logger;
	private readonly IServiceScopeFactory _serviceScopeFactory;
	public Worker(ILogger<Worker> logger, IServiceScopeFactory serviceScopeFactory)
	{
	_logger = logger;
	_serviceScopeFactory = serviceScopeFactory;
	}
	protected override async Task ExecuteAsync(CancellationToken stoppingToken)
	{
	using (var scope = _serviceScopeFactory.CreateScope())
	{
	var dbContext = scope.ServiceProvider.GetRequiredService<ExampleDbContext>();
	//Do something here
	}
	}
	}
	}

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