ASP.NET CAPTCHA implementation

Question

How can I implement CAPTCHA in my ASP.NET WebForm? This is a registration form. I am new to ASP.NET, thanks.

Answer 1

These pages explain how to integrate reCAPTCHA ASP.NET Library with your application. This is the same CAPTCHA used by StackOverflow.

Answer 2

try google

http://www.google.ae/#hl=en&q=asp.net+captcha

anyway links to links

Code to generate CAPTCHA code in ASP.NET?

CAPTCHA Server Control for ASP.NET

Simple Captcha with ASP.Net

Using reCAPTCHA with ASP.NET

Free CAPTCHA ASP.NET Server Management

Answer 3

Just download the recatcha DLL from the link http://code.google.com/p/recaptcha/downloads/list?q=label:aspnetlib-Latest

Then add this DLL to the bin folder of your project as a reference. Then register the control on your page as follows, and

<% @Register TagPrefix = "recaptcha" Namespace = "Recaptcha" Assembly = "Recaptcha"%>

then you can create a control like

You must add the private key and public key provided on the recaptcha website.

Then, in the code behind the Page.IsValid check, if the security code does not match, the control makes Page.IsValid as false.