...
	    
 services.AddIyzicoIntegration(i =>
 {
     i.ApiKey = "your api key";
     i.SecretKey = "your secret key";
     i.BaseUrl = "https://sandbox-api.iyzipay.com";
     i.RestHttpClientLifeTime = ServiceLifetime.Transient;
     i.RestHttpClientV2LifeTime = ServiceLifetime.Transient;
 });

...

        
using Milvasoft.Iyzipay.Model;
using Milvasoft.Iyzipay.Request;
using Milvasoft.Iyzipay.Utils.Abstract;

private readonly IRestHttpClient _restHttpClient;

public PaymentController(IRestHttpClient restHttpClient)
{
    _restHttpClient = restHttpClient;
}

public async Task<IActionResult> CancelPaymentAsync()
{
    CreateCancelRequest request = new()
    {
        ConversationId = "123456789",
        Locale = Locale.TR.ToString(),
        PaymentId = "1",
        Ip = "85.34.78.112"
    };
    
    var cancel = new Cancel(_restHttpClient);
    
    cancel = await cancel.CreateAsync(request).ConfigureAwait(false);
    
    _restHttpClient.Dispose();
    
    if (cancel.Status == Status.SUCCESS.ToString())
        return Ok();
    else
        return BadRequest();
}

IOptions options = new Options
{
   ApiKey = "your api key",
   SecretKey = "your secret key",
   BaseUrl = "https://sandbox-api.iyzipay.com"
}
		
CreatePaymentRequest request = new();
request.Locale = Locale.TR.ToString();
request.ConversationId = "123456789";
request.Price = "1";
request.PaidPrice = "1.2";
request.Currency = Currency.TRY.ToString();
request.Installment = 1;
request.BasketId = "B67832";
request.PaymentChannel = PaymentChannel.WEB.ToString();
request.PaymentGroup = PaymentGroup.PRODUCT.ToString();

PaymentCard paymentCard = new();
paymentCard.CardHolderName = "John Doe";
paymentCard.CardNumber = "5528790000000008";
paymentCard.ExpireMonth = "12";
paymentCard.ExpireYear = "2030";
paymentCard.Cvc = "123";
paymentCard.RegisterCard = 0;
request.PaymentCard = paymentCard;

Buyer buyer = new();
buyer.Id = "BY789";
buyer.Name = "John";
buyer.Surname = "Doe";
buyer.GsmNumber = "+905350000000";
buyer.Email = "[email protected]";
buyer.IdentityNumber = "74300864791";
buyer.LastLoginDate = "2015-10-05 12:43:35";
buyer.RegistrationDate = "2013-04-21 15:12:09";
buyer.RegistrationAddress = "Nidakule Göztepe, Merdivenköy Mah. Bora Sok. No:1";
buyer.Ip = "85.34.78.112";
buyer.City = "Istanbul";
buyer.Country = "Turkey";
buyer.ZipCode = "34732";
request.Buyer = buyer;

Address shippingAddress = new();
shippingAddress.ContactName = "Jane Doe";
shippingAddress.City = "Istanbul";
shippingAddress.Country = "Turkey";
shippingAddress.Description = "Nidakule Göztepe, Merdivenköy Mah. Bora Sok. No:1";
shippingAddress.ZipCode = "34742";
request.ShippingAddress = shippingAddress;

Address billingAddress = new();
billingAddress.ContactName = "Jane Doe";
billingAddress.City = "Istanbul";
billingAddress.Country = "Turkey";
billingAddress.Description = "Nidakule Göztepe, Merdivenköy Mah. Bora Sok. No:1";
billingAddress.ZipCode = "34742";
request.BillingAddress = billingAddress;

List<BasketItem> basketItems = new();
BasketItem firstBasketItem = new();
firstBasketItem.Id = "BI101";
firstBasketItem.Name = "Binocular";
firstBasketItem.Category1 = "Collectibles";
firstBasketItem.Category2 = "Accessories";
firstBasketItem.ItemType = BasketItemType.PHYSICAL.ToString();
firstBasketItem.Price = "0.3";
basketItems.Add(firstBasketItem);

BasketItem secondBasketItem = new();
secondBasketItem.Id = "BI102";
secondBasketItem.Name = "Game code";
secondBasketItem.Category1 = "Game";
secondBasketItem.Category2 = "Online Game Items";
secondBasketItem.ItemType = BasketItemType.VIRTUAL.ToString();
secondBasketItem.Price = "0.5";
basketItems.Add(secondBasketItem);

BasketItem thirdBasketItem = new();
thirdBasketItem.Id = "BI103";
thirdBasketItem.Name = "Usb";
thirdBasketItem.Category1 = "Electronics";
thirdBasketItem.Category2 = "Usb / Cable";
thirdBasketItem.ItemType = BasketItemType.PHYSICAL.ToString();
thirdBasketItem.Price = "0.2";
basketItems.Add(thirdBasketItem);
request.BasketItems = basketItems;

var client = new RequestHttpClient(new HttpClient(),options);

var payment = new Payment(client);

payment = await payment.CreateAsync(request).ConfigureAwait(false);

client.Dispose();