MVCLogin/VCart/Controllers/PlansController.cs

using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json;
using Stripe;

namespace VCart.Controllers
{
    public class PlansController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        public ActionResult Create(PaymentIntentCreateRequest request)
        {
            var paymentIntentService = new PaymentIntentService();
            var paymentIntent = paymentIntentService.Create(new PaymentIntentCreateOptions
            {
                Amount = CalculateOrderAmount(request.Items),
                Currency = "usd",
                // In the latest version of the API, specifying the `automatic_payment_methods` parameter is optional because Stripe enables its functionality by default.
                AutomaticPaymentMethods = new PaymentIntentAutomaticPaymentMethodsOptions
                {
                    Enabled = true,
                },
            });

            return Json(new
            {
                clientSecret = paymentIntent.ClientSecret
                // [DEV]: For demo purposes only, you should avoid exposing the PaymentIntent ID in the client-side code.
                //dpmCheckerLink = $"https://dashboard.stripe.com/settings/payment_methods/review?transaction_id={paymentIntent.ID}"
            });
        }

        private long CalculateOrderAmount(Item[] items)
        {
            // Calculate the order total on the server to prevent
            // people from directly manipulating the amount on the client
            long total = 0;
            foreach (Item item in items)
            {
                total += item.Amount;
            }
            return total;
        }

        public class Item
        {
            [JsonProperty("id")]
            public string Id { get; set; }
            [JsonProperty("Amount")]
            public long Amount { get; set; }
        }

        public class PaymentIntentCreateRequest
        {
            [JsonProperty("items")]
            public Item[] Items { get; set; }
        }
    }
}