Hands-On RESTful Web Services with ASP.NET Core 3

Constructor injection

We have just seen how we can initialize services in our Startup class, but how can we consume these services? By default, the built-in dependency injection container of ASP.NET Core uses the constructor injection pattern to retrieve services. We can modify ValueController to use IPaymentServices by adding the interface as a parameter of the controller constructor:

using Microsoft.AspNetCore.Mvc;namespace SampleAPI.Controllers{    [ApiController]    [Route("[controller]")]    public class ValuesController : ControllerBase    {        private IPaymentService paymentService { get; set; }        public ValuesController(IPaymentService paymentService)        {            this.paymentService = paymentService;        }                public string Get()        {            return paymentService.GetMessage ...