在ASP.NET 5控制器构造函数中注入太多的依赖项可能会影响性能和内存。为了避免这种情况，可以通过将相同类型的依赖项分组来减少注入的数量。例如，可以将所有数据访问类的依赖项分组并将它们注入到单个仓储类中。然后，可以注入这个仓储类到控制器中，而不是注入所有的数据访问依赖项。

以下是一个示例，展示了如何在ASP.NET 5控制器中分组依赖项：

public interface ICustomerRepository
{
    List GetAllCustomers();
}

public class CustomerRepository : ICustomerRepository
{
    private readonly MyAppDbContext _dbContext;

    public CustomerRepository(MyAppDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public List GetAllCustomers()
    {
        return _dbContext.Customers.ToList();
    }
}

public class OrderService : IOrderService
{
    private readonly ICustomerRepository _customerRepository;
    private readonly IOrderRepository _orderRepository;

    public OrderService(ICustomerRepository customerRepository, IOrderRepository orderRepository)
    {
        _customerRepository = customerRepository;
        _orderRepository = orderRepository;
    }

    public List GetOrdersByCustomerId(int customerId)
    {
        var customer = _customerRepository.GetCustomerById(customerId);

        if (customer == null)
        {
            throw new ArgumentException("Invalid customer Id.");
        }

        return _orderRepository.GetOrdersByCustomerId(customerId);
    }
}

public class HomeController : Controller
{
    private readonly IOrderService _orderService;

    public HomeController(IOrderService orderService)
    {
        _orderService = orderService;
    }

    public IActionResult Index()
    {
        var orders = _orderService.GetOrdersByCustomerId(1);

        return View(orders);
    }
}

在上面的示例中，数据