Captcha implementation Using ASP.NET

Posted by Manimaddu under ASP.NET category on 8/7/2014 | Points: 40 | Views : 3629

Post Code |

Search Codes |

Code Home

Hi All...

Here i want implement Captcha using ASP.NET

ShowCaptcha.aspx:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowCapcha.aspx.cs" Inherits="CapchaDemo1.ShowCapcha" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <table>
            <tr>
                <td>
                    <asp:Image ID="imgCaptcha" runat="server" ImageUrl="~/CreateCaptcha.aspx?New=1" />
                </td>
            </tr>
            <tr>
                <td>
                    <asp:TextBox ID="txtCaptcha" runat="server"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td>
                    <asp:Label ID="lblMessage" runat="server"></asp:Label>
                </td>
            </tr>
            <tr>
                <td>
                    <asp:Button ID="btnCaptcha" runat="server" Text="Validate Cpatcha Code" OnClick="btnCaptcha_Click" />
                </td>
            </tr>
        </table>
    </div>
    </form>
</body>
</html>

ShowCaptcha.aspx.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;

namespace CapchaDemo1
{
    public partial class ShowCapcha : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void btnCaptcha_Click(object sender, EventArgs e)
        {
            if (Session["CaptchaCode"] != null && txtCaptcha.Text == Session["CaptchaCode"].ToString())
            {
                lblMessage.ForeColor = Color.Green;
                lblMessage.Text = "Captcha code validated successfully!!";
            }
            else
            {
                lblMessage.ForeColor = Color.Red;
                lblMessage.Text = "Captcha code is wrong!!";
            }
        }
    }
}

CreateCaptcha.aspx:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CreateCaptcha.aspx.cs"
    Inherits="CapchaDemo1.CreateCaptcha" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    </div>
    </form>
</body>
</html>

CreateCaptcha.aspx.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;


namespace CapchaDemo1
{
    public partial class CreateCaptcha : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            CreateCaptchaImage();
        }

        private void CreateCaptchaImage()
        {
            string code = GetRandomText();
            Bitmap bitmap = new Bitmap(200, 60, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
            Graphics g = Graphics.FromImage(bitmap);
            Pen pen = new Pen(Color.Yellow);
            Rectangle rect = new Rectangle(0, 0, 200, 60);
            SolidBrush blue = new SolidBrush(Color.CornflowerBlue);
            SolidBrush black = new SolidBrush(Color.Black);
            int counter = 0;
            g.DrawRectangle(pen, rect);
            g.FillRectangle(blue, rect);
            Random rand = new Random();
            for (int i = 0; i < code.Length; i++)
            {
                g.DrawString(code[i].ToString(), new Font("Tahoma", 10 + rand.Next(15, 20), FontStyle.Italic), black, new PointF(10 + counter, 10));
                counter += 28;
            }
            DrawRandomLines(g);
            bitmap.Save(Response.OutputStream, ImageFormat.Gif);
            g.Dispose();
            bitmap.Dispose();
        }

        /// Method for drawing lines

        private void DrawRandomLines(Graphics g)
        {
            SolidBrush yellow = new SolidBrush(Color.Yellow);
            for (int i = 0; i < 20; i++)
            { g.DrawLines(new Pen(yellow, 1), GetRandomPoints()); }

        }

        /// method for gettting random point position
        private Point[] GetRandomPoints()
        {
            Random rand = new Random();
            Point[] points = { new Point(rand.Next(0, 150), rand.Next(1, 150)), new Point(rand.Next(0, 200), rand.Next(1, 190)) };
            return points;
        }
        /// Method for generating random text of 5 cahrecters as captcha code
        private string GetRandomText()
        {
            StringBuilder randomText = new StringBuilder();
            string alphabets = "012345679ACEFGHKLMNPRSWXZabcdefghijkhlmnopqrstuvwxyz";
            Random r = new Random();
            for (int j = 0; j <= 5; j++)
            { randomText.Append(alphabets[r.Next(alphabets.Length)]); }
            Session["CaptchaCode"] = randomText.ToString();
            return Session["CaptchaCode"] as String;
        }
    }
}

Thank You..

Alert Moderator

Bookmark It

Comments or Responses

Latest Code Snipptes