Adding a Product with a Custom Field to the Cart

To add product to the cart and pass a custom field via querystring the format of the url is the following:

https://www.mydomain.com/BuyNow/cart.aspx?ProductID=1&tbfield=Project99

The “tbfield” passed in the url will be added to the end of the product name similar to how product variants are added to the cart.  If the same base product is added to the cart but with different values in the tbfield, the products will show as separate products (line items) in the cart and invoice.