Hi friends,in this article i will explain about Create
your own captcha image generator in ASP.NET using C#.NET/VB.NET.
In previous articles i explained about How to Create Simple RDLC Report in ASP.NET,Create ,list and Alter the trigger associated with a table with SQL Server? and Binding and Sorting Grid in ASP.NET MVC using Jquery.
Generating captcha take one .aspx page as GenerateCaptcha.aspx and write the following code.
In previous articles i explained about How to Create Simple RDLC Report in ASP.NET,Create ,list and Alter the trigger associated with a table with SQL Server? and Binding and Sorting Grid in ASP.NET MVC using Jquery.
Generating captcha take one .aspx page as GenerateCaptcha.aspx and write the following code.
GenerateCaptcha.aspx.cs:
using System.IO;
using System.Drawing;
using
System.Drawing.Drawing2D;
using System.Drawing.Imaging;
public partial class GenerateCaptcha : System.Web.UI.Page
{
protected
void Page_Load(object
sender, EventArgs e)
{
Response.Clear();
int height = 40;
int width = 110;
Bitmap bmp = new
Bitmap(width, height);
RectangleF rectf = new
RectangleF(12, 6, 0, 0);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
g.SmoothingMode = SmoothingMode.AntiAlias;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.DrawString(Session["captcha"].ToString(), new Font("Cambria", 13, FontStyle.Bold), Brushes.Red,
rectf);
g.DrawRectangle(new Pen(Color.Green), 1, 1, width - 15, height -10);
g.Flush();
Response.ContentType =
"image/jpeg";
bmp.Save(Response.OutputStream,
ImageFormat.Jpeg);
g.Dispose();
bmp.Dispose();
}
}
|
Take .aspx where you want to use captcha.
UseCaptcha.aspx
UseCaptcha.aspx
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Create
your own captcha image generator in ASP.NET using C#.NET/VB.NET</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1"
runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1"
runat="server">
<ContentTemplate>
<table>
<tr>
<td style="height: 50px; width: 100px;">
<asp:Image ID="imgCaptcha"
runat="server"
/>
</td>
<td valign="middle">
<asp:Button ID="btnRefresh" runat="server" Text="Refresh" OnClick="btnRefresh_Click" />
</td>
</tr>
</table>
</ContentTemplate>
</asp:UpdatePanel>
Enter Captcha:
<asp:TextBox ID="txtCaptcha"
runat="server"></asp:TextBox><br />
<asp:Button ID="btnSubmit"
runat="server"
Text="Submit"
OnClick="btnSubmit_Click"
/>
</div>
</form>
</body>
</html>
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UseCaptcha.aspx.cs
using System.Text;
using System.Drawing.Imaging;
public partial class UseCaptcha : System.Web.UI.Page
{
protected
void Page_Load(object
sender, EventArgs e)
{
if (!IsPostBack)
{
FillCaptcha();
}
}
void
FillCaptcha()
{
try
{
Random random = new
Random();
string combination = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
StringBuilder captcha = new
StringBuilder();
for (int i = 0; i
< 6; i++)
captcha.Append(combination[random.Next(combination.Length)]);
Session["captcha"] = captcha.ToString();
imgCaptcha.ImageUrl = "GenerateCaptcha.aspx";
}
catch
{
throw;
}
}
protected
void btnRefresh_Click(object sender, EventArgs e)
{
FillCaptcha();
}
protected
void btnSubmit_Click(object
sender, EventArgs e)
{
if (Session["captcha"].ToString()
!= txtCaptcha.Text)
Response.Write("Enter Valid Captcha Code");
FillCaptcha();
}
}
|
The output of the above page as shown in the below figure.
You can download the code by clicking on the below Download image.
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