Use Google Captcha in your ASP.NET Project in C#

Using captcha in your site making your site much better secure against hackers and their scripts. So in this article I will show you how to use Google recaptcha in your asp.net project.

First download the ReCaptcha.dll and add as a reference in your project. You can download this from here. Before starting this you need to register yourself to get a public & private key of your Google apps.

Now add the register code in your aspx page.

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

And now add the following code in your aspx code, where you want to place your captcha.

<asp:Label Visible="false" ID="lblResult" runat="server" />

<recaptcha:recaptchacontrol id="recaptcha" runat="server" publickey="<Your public key>"

privatekey="<Your private key>" Theme="clean" />

In the code behind on a button click add the the code..

protected void btnSubmit_Click(object sender, EventArgs e)

{
      recaptcha.Validate();

      if(Page.IsValid && recaptcha.IsValid)

      {

           lblResult.Text = "You Got It!";

           lblResult.ForeColor = Drawing.Color.Green;

      }

      else

      {

           lblResult.Text = "Incorrect";

           lblResult.ForeColor = Drawing.Color.Red;

      }     

}

Your captcha is ready. Run the project and have fun.

Output :

Download the source code here.

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