c# 9中，如何声明一个灵活的接口？

Question

I'm using Entity Framework Core and want to have two different implementations of SpeakerQueries that each use a different EF Core data context.

My original class only included one data context, but I've extended such that it now includes two.

Here is my c# interface defined as follows:

public interface ISpeakerQueries
{
    IQueryable<Speaker> GetSpeakers(
        [ScopedService] ApplicationDbContext context, [ScopedService] ApplicationDbContextAlt contextAlt);
    ...

I really only want one data context to be called with each method but not sure how to define my interface to allow that to happen.

In other words, I want my concrete implementations of GetSpeakers to be

public class SpeakerQueriesAlt : ISpeakerQueries
{
    [UseApplicationDbContextAlt]
    [UsePaging]
    public IQueryable<Speaker> GetSpeakers(
        [ScopedService] ApplicationDbContextAlt context)
    { ...

or

public class SpeakerQueries : ISpeakerQueries
{
    [UseApplicationDbContext]
    [UsePaging]
    public IQueryable<Speaker> GetSpeakers(
        [ScopedService] ApplicationDbContext context)
    { ...

I think I can do this, but not sure how I should declare the interface. The interface I declared at the top does not work because it expects two parameters and not one.

Answer 1

Are you looking into HotChocolate and their workshop sample? If not then ignore rest:)

Using method injections is the correct way of injecting services into the HotChocolate library for execution.

I'm trying to understand what are trying to achieve? Are you trying to (A) create two query endpoints that will use different dbcontext and only return data for that spesific context? Or are you trying to create (B) one query that will return all speakers for both dbcontexts?

In case of A then I think you can easily extract the interface from that, but you will probably have to give them two different names.

If B then I would either create a service that injects the two different contexts and have the responsiblity to join the results together. Or you can create your own Middleware/pipeline, Or even better create 3 graphql servers where Server A returns data from Context1 and Server B returns data from context 2 and your server C which is public is using schema stitching.

As mentioned if this is not HC and Graphql just ignore my answer