Question

I have classes such as AccountsController, ProductsController etc that all inherit from BaseController. Unity sets up my services as needed. These classes also all require a _sequence service. As it is a common requirement for all classes I would like to code this in the BaseController.

public class AccountsController : BaseController
{
    public AccountsController(
        IService<Account> accountService) {
        _account = accountService;
    }

public class ProductsController : BaseController
{
    public ProductsController(
        IService<Account> productService) {
        _product = productService;
    }


public class BaseController : Controller
{
    public IService<Account> _account;
    public IService<Product> _product;
    protected ISequenceService _sequence;

    public BaseController(
        ISequenceService sequenceService) {
        _sequence = sequenceService;
    }

But how can I do this? Should I set up a call to the BaseController inside the constructors of each of the AccountsController and ProductsController?

Answer 1

You can chain constructors:

public class ProductsController : BaseController
{
    public ProductsController(
        IService<Account> productService) : base(productService)
    {
        _product = productService;
    }
}

Note that the chained BaseController (using the base keyword) has been passed the productService parameter, tough this can be anything.

Update:

You could do the following (poor mans’ dependency injection):

public class ProductsController : BaseController
{
    public ProductsController(
        IService<Account> productService) : base(new SequenceService())
    {
        _product = productService;
    }
}

Or, pass in the dependency on ISequenceService through your inheriting types:

public class ProductsController : BaseController
{
    public ProductsController(
        IService<Account> productService, ISequenceService sequenceService) 
        : base(sequenceService)
    {
        _product = productService;
    }
}