Question

Ok, I cannot get this. I’ve looked at it and I don’t see why it’s out of bounds. I get the error at paypalItems[paypalItems.Length] = new PaymentDetailsItemType

PaymentDetailsItemType[] paypalItems = new PaymentDetailsItemType[order.OrderItems.Count];

for (int i = 0; i < order.OrderItems.Count; i++)
{

    paypalItems[i] = new PaymentDetailsItemType
    {
        Name = order.OrderItems[i].Name,
        Amount = ApiUtility.CreateBasicAmount(order.OrderItems[i].Price),
        Description = order.OrderItems[i].Name,
        Number = order.OrderItems[i].Sku,
    };
}

// paymentItems now has 1 item...now to the if statement:

if (giftCardsTotal != 0)
{
    // add Coupons & Discounts line item
    paypalItems[paypalItems.Length] = new PaymentDetailsItemType
                                              {
                                                  Name = "Gift Cards",
                                                  Amount = ApiUtility.CreateBasicAmount(giftCardsTotal),
                                                  Description = "Gift Cards"
                                              };
}

UPDATED: I changed the size of the array..now it’s all good. No need for the -1

PaymentDetailsItemType[] paypalItems = new PaymentDetailsItemType[order.OrderItems.Count + 1];

            for (int i = 0; i < order.OrderItems.Count; i++)
            {
                paypalItems[i] = new PaymentDetailsItemType
                {
                    Name = order.OrderItems[i].Name,
                    Amount = ApiUtility.CreateBasicAmount(order.OrderItems[i].Price),
                    Description = order.OrderItems[i].Name,
                    Number = order.OrderItems[i].Sku,
                };
            }

        // paymentItems now has 1 item...now to the if statement:

            if (giftCardsTotal != 0)
            {
                paypalItems[paypalItems.Length -1] = new PaymentDetailsItemType
                {
                    Name = "Certificates",
                    Amount = ApiUtility.CreateBasicAmount(giftCardsTotal),
                    Description = "Certificates"
                };
            }

Answer 1

Because they are 0-indexed, so first one is the 0 and last one is length-1.

This is true for almost any programming language..

It seems that first you fill up an array by trasforming elements from another one and then you want to replace last one. Maybe you intended to append an element to the end?

In that case you should build it larger:

PaymentDetailsItemType[] paypalItems = new PaymentDetailsItemType[order.OrderItems.Count+1];

then fill it as you did:

for (int i = 0; i < order.OrderItems.Count; i++)
{
  ...
}

then set the last one:

paypalItems[paypalItems.Length-1] = ..