In this article, you learn how to create captcha image in asp.net using c#
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Captcha
{
public partial class Captcha: System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Bitmap objBitmap = new Bitmap(131, 81);
Graphics objGraphics = Graphics.FromImage(objBitmap);
objGraphics.Clear(Color.White);
Random objRandom = new Random();
objGraphics.DrawLine(Pens.Black, objRandom.Next(0, 50), objRandom.Next(10, 30), objRandom.Next(0, 200), objRandom.Next(0, 50));
objGraphics.DrawRectangle(Pens.Blue, objRandom.Next(0, 20), objRandom.Next(0, 20), objRandom.Next(50, 80), objRandom.Next(0, 20));
objGraphics.DrawLine(Pens.Blue, objRandom.Next(0, 20), objRandom.Next(10, 50), objRandom.Next(100, 200), objRandom.Next(0, 80));
Brush objBrush = default (Brush);
HatchStyle[] aHatchStyles = new HatchStyle[]
{
HatchStyle.BackwardDiagonal, HatchStyle.Cross, HatchStyle.DashedDownwardDiagonal, HatchStyle.DashedHorizontal,
HatchStyle.DashedUpwardDiagonal, HatchStyle.DashedVertical,
HatchStyle.DiagonalBrick, HatchStyle.DiagonalCross, HatchStyle.Divot, HatchStyle.DottedDiamond, HatchStyle.DottedGrid,
HatchStyle.ForwardDiagonal, HatchStyle.Horizontal,
HatchStyle.HorizontalBrick, HatchStyle.LargeCheckerBoard, HatchStyle.LargeConfetti, HatchStyle.LargeGrid, HatchStyle.LightDownwardDiagonal,
HatchStyle.LightHorizontal
};
RectangleF oRectangleF = new RectangleF(0, 0, 300, 300);
objBrush = new HatchBrush(aHatchStyles[objRandom.Next(aHatchStyles.Length - 3)], Color.FromArgb((objRandom.Next(100, 255)), (objRandom.Next(100,
255)), (objRandom.Next(100, 255))), Color.White);
objGraphics.FillRectangle(objBrush, oRectangleF);
string captchaText = string.Format("{0:X}", objRandom.Next(500000, 700000));
Session["CaptchaVerify"] = captchaText.ToLower();
Font objFont = new Font("Courier New", 15, FontStyle.Bold);
objGraphics.DrawString(captchaText, objFont, Brushes.Black, 21, 21);
objBitmap.Save(Response.OutputStream, ImageFormat.Gif);
}
}
}
<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Register.aspx.cs" Inherits="Captcha.Register" %>
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<table>
<tr>
<td colspan="2">User Registration
</td>
</tr>
<tr>
<td>Full Name
</td>
<td>
<asp:TextBox runat="server" ID="txtFullName"></asp:TextBox>
</td>
</tr>
<tr>
<td>Email Id
</td>
<td>
<asp:TextBox runat="server" ID="txtEmail"></asp:TextBox>
</td>
</tr>
<tr>
<td>User Name
</td>
<td>
<asp:TextBox runat="server" ID="txtUserName"></asp:TextBox>
</td>
</tr>
<tr>
<td>Password
</td>
<td>
<asp:TextBox runat="server" ID="txtPassword" TextMode="Password"></asp:TextBox>
</td>
</tr>
<tr>
<td>Verification Code
</td>
<td>
<asp:Image ID="Image2" runat="server" Height="55px" ImageUrl="~/Captcha.aspx" Width="186px" />
<br />
<asp:Label runat="server" ID="lblCaptchaMessage"></asp:Label>
</td>
</tr>
<tr>
<td>Enter Verifaction Code
</td>
<td>
<asp:TextBox runat="server" ID="txtVerificationCode"></asp:TextBox>
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button runat="server" ID="btnSubmit" Text="Submit" OnClick="btnSubmit_Click" />
</td>
</tr>
</table>
</asp:Content>
Here is captcha is right otherwise it is wrong.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Captcha
{
public partial class Register: System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{}
protected void btnSubmit_Click(object sender, EventArgs e)
{
if (txtVerificationCode.Text.ToLower() == Session["CaptchaVerify"].ToString())
{
Response.Redirect("Default.aspx");
}
else
{
lblCaptchaMessage.Text = "Please enter correct captcha !!!!!";
lblCaptchaMessage.ForeColor = System.Drawing.Color.Red;
}
}
}
}
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Captcha._Default" %>
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
<br />
<asp:Label runat="server" ID="lblCaptchaMessage" ForeColor="Green">
</asp:Label>
</asp:Content>
using System;
using System.Web.UI;
namespace Captcha
{
public partial class _Default: Page
{
protected void Page_Load(object sender, EventArgs e)
{
lblCaptchaMessage.Text = "Success";
lblCaptchaMessage.ForeColor = System.Drawing.Color.Green;
}
}
} How To Create Captcha Image With asp.net using c#
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"
Inherits="_Default" %>
<!DOCTYPE html>
<html>
<head>
<title>Asp.Net Repeater Control</title>
</head>
<body>
<form id="form1" runat="server">
<div style="font:13px Verdana;width:310px;">
<asp:ScriptManager ID="scriptManager" runat="server" EnablePageMethods="true" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<h3>Asp.Net Repeater Control</h3>
<%--THE REPEATER CONTROL.--%>
<asp:Repeater id="rp" runat="server">
<%--HEADER OF THE REPEATER--%>
<HeaderTemplate>
<table border="0" width="200px">
</HeaderTemplate>
<%--SHOWING ITEMS--%>
<ItemTemplate>
<tr>
<td style="padding:2px;
border:solid 1px #CCC;">
<asp:Label Text='<%# Container.DataItem.ToString() %>'
runat="server"></asp:Label>
</td>
</tr>
</ItemTemplate>
<%--ALTERNATE TEMPLATE (SHOWING ITEMS IN DIFFERENT COLOR--%>
<AlternatingItemTemplate>
<tr>
<td style="padding:2px;
border:solid 1px #CCC;
background:#EAF7FB;
width:200px;">
<asp:Label Text='<%# Container.DataItem.ToString() %>'
runat="server"></asp:Label>
</td>
</tr>
</AlternatingItemTemplate>
<%--REPEATER FOOTER--%>
<FooterTemplate>
</table>
<div style="padding:20px 0;">
<asp:Label ID="lblFoot" runat="server"></asp:Label>
</div>
</FooterTemplate>
</asp:Repeater>
<%--BUTTON CONTROL--%>
<asp:Button ID="btVF" Text="View Files" AutoPostBack="true"
OnClick="Show"
Font-Names="sanserif"
Font-Italic="true"
Font-Size="155%"
runat="server" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="PostBackTrigger" />
</Triggers>
</asp:UpdatePanel>
</div>
</form>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e) {}
protected void Show(object sender, EventArgs e)
{
DirectoryInfo Folder = new DirectoryInfo(Server.MapPath("Files\\"));
FileInfo[] fileList = Folder.GetFiles("*.*");
//BIND THE FILE LIST WITH THE REPEATER CONTROL.
rp.DataSource = fileList;
rp.DataBind();
}
}
Adding the <AlternatingTemplate> below the <ItemTemplate> will show files with a different background color for every alternate row.
<AlternatingItemTemplate>
<div style="padding:3px; border:solid 1px #FFF; background:#black">
<asp:Label Text='<%# Container.DataItem.ToString() %>' runat="server"></asp:Label>
</div>
</AlternatingItemTemplate>
</AlternatingItemTemplate>
<SeparatorTemplate><hr />
</SeparatorTemplate>
Add the <HeaderTemplate> element just above the <ItemTemplate>
<HeaderTemplate>
<div style="padding-bottom:20px"><strong>Files</strong> (Header)</div>
</HeaderTemplate>
Repeater with <FooterTemplate> element
<FooterTemplate>
<div style="padding-top:20px"><asp:Label ID="lblFooter" runat="server"></asp:Label></div>
</FooterTemplate>
Code Behind In C#
Control ft = rp.Controls[rep.Controls.Count - 1].Controls[0];
Label lbl_Footer = ft.FindControl("lblFooter") as Label;
lbl_Footer.Text = "Showing total <b>" + fileList.Length + "</b> files in the Footer.";