Cannot consume scoped service 'MyDbContext' from singleton 'Microsoft.AspNetCore.Hosting.Internal.HostedServiceExecutor'

Question

I\'ve build a background task in my ASP.NET Core 2.1 following this tutorial: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/host/hosted-services?view=aspnetcore-

Answer 1

You need to inject IServiceScopeFactory to generate a scope. Otherwise you are not able to resolve scoped services in a singleton.

using (var scope = serviceScopeFactory.CreateScope())
{
  var context = scope.ServiceProvider.GetService();
}

Edit: It's perfectly fine to just inject IServiceProvider and do the following:

using (var scope = serviceProvider.CreateScope()) // this will use `IServiceScopeFactory` internally
{
  var context = scope.ServiceProvider.GetService();
}

The second way internally just resolves IServiceProviderScopeFactory and basically does the very same thing.