ASP.NET CAPTCHA implementation

Question

How can I implement a CAPTCHA in my ASP.NET WebForm? It is a registration form. I am a beginner in ASP.NET, thanks.

Answer 1

This pages explains how to integrate the 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

anyways helping links are

Code to create CAPTCHA code in ASP.NET?

A CAPTCHA Server Control for ASP.NET

Simple Captcha with ASP.Net

Using reCAPTCHA with ASP.NET

Free CAPTCHA ASP.NET server control

Answer 3

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

Then add that DLL into the bin folder of your project as reference. Then register the control on your page as specified below and

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

then you can create the control as

You have to add the private key and public key provided in the recaptcha website.

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