Code to create captcha in asp.net
1 .Add default.aspx Page name as Chaptcha.aspx. On page load
using System.Drawing;
using System.Drawing.Text;
using System.Drawing.Imaging;
try
{
Bitmap objBMP = new System.Drawing.Bitmap(100, 40);
Graphics objGraphics = System.Drawing.Graphics.FromImage(objBMP);
objGraphics.Clear(Color.LightPink);
objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias;
//' Configure font to use for text
Font objFont = new Font("verdana", 14, FontStyle.Bold);
string randomStr = "";
Random random = new Random();
int length = 2;
for (int i = 0; i < length; i++)
{
randomStr += ((char)random.Next(97, 122)).ToString();
randomStr += ((char)random.Next(65, 91)).ToString();
randomStr += random.Next(2, 9);
}
Session.Add("randomStr", randomStr);
//' Write out the text
objGraphics.DrawString(randomStr, objFont, Brushes.DarkSlateBlue, 4, 4);
//' Set the content type and return the image
Response.ContentType = "image/GIF";
objBMP.Save(Response.OutputStream, ImageFormat.Gif);
objFont.Dispose();
objGraphics.Dispose();
objBMP.Dispose();
}
catch
{
}
}
2. add default2.aspx
Add in <body>
<img id="Image1" runat="server" />
<asp:Button ID="btnRefresh" runat="server" Text="Refresh"
PostBackUrl="~/default2.aspx" onclick="btnRefresh_Click" />
3. default2.aspx.cs
1 .Add default.aspx Page name as Chaptcha.aspx. On page load
using System.Drawing;
using System.Drawing.Text;
using System.Drawing.Imaging;
try
{
Bitmap objBMP = new System.Drawing.Bitmap(100, 40);
Graphics objGraphics = System.Drawing.Graphics.FromImage(objBMP);
objGraphics.Clear(Color.LightPink);
objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias;
//' Configure font to use for text
Font objFont = new Font("verdana", 14, FontStyle.Bold);
string randomStr = "";
Random random = new Random();
int length = 2;
for (int i = 0; i < length; i++)
{
randomStr += ((char)random.Next(97, 122)).ToString();
randomStr += ((char)random.Next(65, 91)).ToString();
randomStr += random.Next(2, 9);
}
Session.Add("randomStr", randomStr);
//' Write out the text
objGraphics.DrawString(randomStr, objFont, Brushes.DarkSlateBlue, 4, 4);
//' Set the content type and return the image
Response.ContentType = "image/GIF";
objBMP.Save(Response.OutputStream, ImageFormat.Gif);
objFont.Dispose();
objGraphics.Dispose();
objBMP.Dispose();
}
catch
{
}
}
Add in <body>
<img id="Image1" runat="server" />
<asp:Button ID="btnRefresh" runat="server" Text="Refresh"
PostBackUrl="~/default2.aspx" onclick="btnRefresh_Click" />
3. default2.aspx.cs
on page load
Image1.Src = "Chaptcha.aspx";
protected void btnRefresh_Click(object sender, EventArgs e)
{
txtcode.Text = "";
Image1.Src = "Chaptcha.aspx";
}
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