Page 374 item 6 Some services are not able to be constructed.

[mgerber2]

Getting this error:

Unhandled exception. System.AggregateException: Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Northwind.Repositories.ICustomerRepository Lifetime: Scoped ImplementationType: Northwind.Repositories.CustomerRepository': Unable to resolve service for type 'Northwind.EntityModels.NorthwindContext' while attempting to activate 'Northwind.Repositories.CustomerRepository'.)
---> System.InvalidOperationException: Error while validating the service descriptor 'ServiceType: Northwind.Repositories.ICustomerRepository Lifetime: Scoped ImplementationType: Northwind.Repositories.CustomerRepository': Unable to resolve service for type 'Northwind.EntityModels.NorthwindContext' while attempting to activate 'Northwind.Repositories.CustomerRepository'.

Also getting

Unable to connect to web server 'https'. The web server is no longer running.

This happens when I start the web server without debugging.

This was working before I started the Understanding CORS section.

If you can tell me how to resolve this and what you did to determine the issue it would be much appreciated.

[markjprice]

Some ways you can troubleshoot:

1. Comment out or otherwise remove any changes you made since starting the Understanding CORS section.
2. Compare your code to the projects in the GitHub respository.
3. From the exception, it looks like you are not registering the NorthwindContext so the CustomerRepository cannot get an instance of it. Check that you are still calling builder.Services.AddNorthwindContext();. Maybe you accidentally removed that statement when adding the CORS code.
4. Make sure you are running all dependent projects. For example, before running the MVC project, make sure the WebApi project is running, otherwise when the MVC home page tries to call the web service, you will get an error saying that it isn't running.