A Single DLL ASP.NET Server Control will do everything for you if you want to develop an e-commerce web application with PayPal Website Payments Standard. Enhanced Design time SMART Tag GUI will guide you to generate any kind of PayPal supported buttons (BuyNow Button, DONATION Button, Add to Cart Button, Subscription Button, Cancel Subscription Button, Upload Complete Cart Button, View Cart Button). Strong Object Oriented Programming Interface. PayPal Encrypted Website Payments buttons can be generated on the fly either from design time GUI or programmatically by providing the Certificates parameters. If you do not have PKCS12 and PEM certificates, Guess What! The Design time GUI will generate those certificates for you. You just need to stick to this control.
IPN & PDT is considered as if those are the very control's server side events where all IPN & PDT variables are available as the properties of Event Argument Class. Thus, a developer can design a single page for the complete eCommerce Logic by using a PayPal Button in a web form and attach event handler methods for IPN/PDT events. Server side Click Event makes this control more programmable. Very organized collection classes and composite properties are available for providing an object oriented pleasure to the web application developers.
Sample eCommerce Web Applications are available as a Visual Studio 2005/2008 project solution in C#.NET and VB.NET languages so that your can develop your eShop directly using the sample codes, no need to start from Scratch.
Post Click Behaviour property : You can disable or make invisible the PayPal button immediately after the first click so that your customer cannot repeatedly click on the button. A public method named Submit() available for submitting the button which can be called from your server side code.