Pay Pal Integration in asp.net website using .net framework 4.8

[pujaparekh]

hi,

I have an asp.net (web forms) website built using .net framework 4.8 (C#) in visual studio 2019. I am not able to integrate PayPalCheckoutSdk and PayPalHttp sdk in my website.  There is a default.aspx page with pay pal button which when clicked should open pay pal login page and after user approves payment, it should return to complete.aspx page. I have 2 other pages called CreatePayPalOrder.aspx and ExecutePayPalPayment.aspx which are called when paypal's createOrder and onApprove functions are called. Now when I click on pay pal button on default page, it tries to open a pay pal login page but the pay pal pop just loads indefinitely. Please help as to what is wrong with the code. I reviewed code on github and did numerous google searches but all to a waste. Also, am not sure if the flow of code is correct. I posted a ticket to pay pal support but they are totally hopeless. 

Here is my code

Default.aspx

<div id="paypal-button-container"></div>

<script src="https://www.paypal.com/sdk/js?client-id=mySandboxClientId&currency=AUD"> </script><script>

paypal.Buttons({

env: 'sandbox', /* sandbox | production */
style: {
layout: 'horizontal', // horizontal | vertical
size: 'responsive', /* medium | large | responsive*/
shape: 'pill', /* pill | rect*/
color: 'gold', /* gold | blue | silver | black*/
fundingicons: false, /* true | false */
tagline: false /* true | false */
},

// Set up the transaction

createOrder: function (data) {
return fetch('/CreatePayPalOrder', {
method: 'post'
}).then(function (res) {
return res.json();
}).then(function (orderData) {
return orderData.Id; // Use the same key name for order ID on the client and server
});
},

onApprove: function (data) {
return fetch('/ExecutePayPalPayment', {
method: 'post'
}).then(function (res) {
return res.json();
}).then(function (orderData) {
alert('Transaction approved by ' + orderData.payer_given_name);
});
},

// Buyer cancelled the payment
onCancel: function (data) {
 alert(data);
},

// An error occurred during the transaction
onError: function (err) {
alert(err);
}

}).render('#paypal-button-container');</script>

CreatePayPalOrder.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{
CreateOrder().Wait();

string OrderId = Session["PayPalOrderId"].ToString();

GetOrder(OrderId).Wait();
}

public async Task<HttpResponse> CreateOrder()
{
try
{
var request = new OrdersCreateRequest();
request.Prefer("return=representation");
request.RequestBody(BuildRequestBody());

//3. Call PayPal to set up a transaction
var response = await PayPalClient.client().Execute(request); // the code hangs on this line and never comes out

var result = response.Result<Order>();

Session["PayPalOrderId"] = result.Id;

Debug.WriteLine("Status: {0}", result.Status);
Debug.WriteLine("Order Id: {0}", result.Id);
Debug.WriteLine("Intent: {0}", result.CheckoutPaymentIntent);
Debug.WriteLine("Links:");
foreach (LinkDescription link in result.Links)
{
Debug.WriteLine("\t{0}: {1}\tCall Type: {2}", link.Rel, link.Href, link.Method);
}
AmountWithBreakdown amount = result.PurchaseUnits[0].AmountWithBreakdown;
Debug.WriteLine("Total Amount: {0} {1}", amount.CurrencyCode, amount.Value);

return response;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}

private OrderRequest BuildRequestBody()
{
OrderRequest orderRequest = new OrderRequest()
{
CheckoutPaymentIntent = "CAPTURE",

ApplicationContext = new ApplicationContext
{
BrandName = "MyBrand",
LandingPage = "BILLING",
UserAction = "CONTINUE",
ReturnUrl = "https://localhost:44316/Complete",
CancelUrl = "https://localhost:44316/Default"
},
PurchaseUnits = new List<PurchaseUnitRequest>
{
new PurchaseUnitRequest{
ReferenceId = "B456",
AmountWithBreakdown = new AmountWithBreakdown
{
CurrencyCode = "AUD",
Value = "15.00"
}
}
}
};

return orderRequest;
}

public async Task<HttpResponse> GetOrder(string orderId)
{
try
{
OrdersGetRequest request = new OrdersGetRequest(orderId);
//3. Call PayPal to get the transaction
var response = await PayPalClient.client().Execute(request);
//4. Save the transaction in your database. Implement logic to save transaction to your database for future reference.
var result = response.Result<Order>();
Debug.WriteLine("Retrieved Order Status");
Debug.WriteLine("Status: {0}", result.Status);
Debug.WriteLine("Order Id: {0}", result.Id);
Debug.WriteLine("Intent: {0}", result.CheckoutPaymentIntent);
Debug.WriteLine("Links:");
foreach (LinkDescription link in result.Links)
{
Debug.WriteLine("\t{0}: {1}\tCall Type: {2}", link.Rel, link.Href, link.Method);
}
AmountWithBreakdown amount = result.PurchaseUnits[0].AmountWithBreakdown;
Debug.WriteLine("Total Amount: {0} {1}", amount.CurrencyCode, amount.Value);

return response;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}

ExecutePayPalPayment.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{
string OrderId = Session["PayPalOrderId"].ToString();

CaptureOrder(OrderId).Wait();
}

public async Task<HttpResponse> CaptureOrder(string OrderId)
{
try
{
var request = new OrdersCaptureRequest(OrderId);
request.Prefer("return=representation");
request.RequestBody(new OrderActionRequest());
//3. Call PayPal to capture an order
var response = await PayPalClient.client().Execute(request);
//4. Save the capture ID to your database. Implement logic to save capture to your database for future reference.

var result = response.Result<Order>();
Debug.WriteLine("Status: {0}", result.Status);
Debug.WriteLine("Order Id: {0}", result.Id);
Debug.WriteLine("Intent: {0}", result.CheckoutPaymentIntent);
Debug.WriteLine("Links:");
foreach (LinkDescription link in result.Links)
{
Debug.WriteLine("\t{0}: {1}\tCall Type: {2}", link.Rel, link.Href, link.Method);
}
Debug.WriteLine("Capture Ids: ");

AmountWithBreakdown amount = result.PurchaseUnits[0].AmountWithBreakdown;
Debug.WriteLine("Buyer:");

return response;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}

PayPalClient.cs

public class PayPalClient
{
/**
Set up PayPal environment with sandbox credentials.
In production, use LiveEnvironment.
*/
public static PayPalEnvironment environment()
{
return new SandboxEnvironment("mySandboxClientId", "mySandboxSecret");
}

/**
Returns PayPalHttpClient instance to invoke PayPal APIs.
*/
public static HttpClient client()
{
return new PayPalHttpClient(environment());
}

public static HttpClient client(string refreshToken)
{
return new PayPalHttpClient(environment(), refreshToken);
}

/**
Use this method to serialize Object to a JSON string.
*/
public static String ObjectToJSONString(Object serializableObject)
{
MemoryStream memoryStream = new MemoryStream();
var writer = JsonReaderWriterFactory.CreateJsonWriter(
memoryStream, Encoding.UTF8, true, true, " ");
DataContractJsonSerializer ser = new DataContractJsonSerializer(serializableObject.GetType(), new DataContractJsonSerializerSettings { UseSimpleDictionaryFormat = true });
ser.WriteObject(writer, serializableObject);
memoryStream.Position = 0;
StreamReader sr = new StreamReader(memoryStream);
return sr.ReadToEnd();
}
}

[sp8eu]

Hi, Did you ever find a solution to this problem? I'm experiencing the same problem. I've seen other links in this forum on this topic and it looks like PayPal don't provide a solution that works. Their sample code looks like it's only suitable for desktop type apps.