Dependency injection with constructor chaining

Question

Currently I have a simple generic abstract class with one service parameter in constructor which is resolved by dependency injection.

public abstract class CosmosCommandHandler<T>
{
    protected readonly ICosmosStore<T> _cosmosStore;

    protected CosmosCommandHandler(ICosmosStore<T> cosmosStore)
    {
      _cosmosStore = cosmosStore;
    }
}

and some concrete class inheriting from it

public class FooCommandHandler : CosmosCommandHandler<Foo> 
{
  private readonly IFooService _fooService;

  public FooCommandHandler(ICosmosStore<Foo> cosmosStore, IFooService fooService) 
      : base(cosmosStore)
  {
    _fooService = fooService;
  }
}

This is all fine, but I want to add a new service to abstract class and resolve it with DI as well. My idea is that I should use constructor chaining for this, but it's not working out. Something like this.

public abstract class CosmosCommandHandler<T>
{
    private readonly IAuditService _auditService;
    protected readonly ICosmosStore<T> _cosmosStore;

    private CosmosCommandHandler(ICosmosStore<T> cosmosStore, IAuditService auditService)
    {
        _cosmosStore = cosmosStore;
        _auditService = auditService;
    }

    protected CosmosCommandHandler(ICosmosStore<T> cosmosStore) 
        : this(cosmosStore, IAuditService auditService)
    {
    }
}

Obviously I could just pass the IAuditService from FooCommandHandler just like ICosmosStore , but that doesn't seem right as FooCommandHandler has nothing to do with IAuditService . It is out of its scope.

Is this possible to achieve?

Answer 1

If IAuditService is out of the FooCommandHandler scope, then create child of your CosmosCommandHandler class which will have that IAuditService . And that child also could be abstract class. Also, you could create additional overloaded constructor for your CosmosCommandHandler class - and that FooCommandHandler class does not need to use it. But that also breaks the concept of inheritance because FooCommandHandler class has nothing to do with IAuditService .