Captcha code with refresh button demo example in C#

Question

1.00/5 (2 votes)

See more:

Hi,

i want captcha code with refresh button...refresh button should work with update panel so that only the captcha image will change partially.....i searched in net but refresh button will work with full postback only.....actually here i want in partial postback.....

and no use of dll.......

please help me

Posted 8-Apr-13 18:59pm

Member 9155255

Updated 8-Apr-13 20:06pm

v2

Add a Solution

Comments

Sergey Alexandrovich Kryukov 9-Apr-13 2:11am

Did you try to find anything?
—SA

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sergey Alexandrovich Kryukov · Answer 1 · 2013-04-08T20:10:00

Solution 1

This CodeProject article, for example: Simple CAPTCHA, Create your own in C#[^].

—SA

Posted 8-Apr-13 20:10pm

Sergey Alexandrovich Kryukov

Comments

Member 9155255 9-Apr-13 2:23am

The link what u send....that code i have already implemented....but i got stuck in refresh button....the requirement is along with captcha image i want one refresh button...when u click on refresh button the captcha image should change with partial postback(fullpostback should not happen)...this i should do without using dll.....

esmael taher 13-Oct-13 2:48am

hi my friends.I have a same problem with reloading captcha image without reloadin other items. can any one explain me "How I Can Reload Only Captch aImage?"

Sergey Alexandrovich Kryukov 9-Apr-13 2:34am

I have no information on where did you stuck and why...
—SA

Member 9155255 9-Apr-13 2:46am

in ur example refreshing captcha image is not there,before submiting to the page.....that i want ....can u help me

Sergey Alexandrovich Kryukov 9-Apr-13 11:00am

I did not pay attention for that, but... is it really difficult to add refreshing?
I guess, you would need drawing alternative captcha image over and over on the user request. But look, if it is already done once in the available code, why not adding a small modification of the code to do repeat it over and over? You should never expect that someone gives you exactly what you want (people don't develop software on your orders); you are supposed to contribute to implementation of your own goals...

So, how about the following: you try to create the modified code and ask another question if you face a brick wall?

—SA

Member 9155255 10-Apr-13 1:23am

i have added refresh button along with captcha image within update panel....if i put in update panel its not going to work....if i not put in update panel it will work....but for full postback we dont want...because if we use that in any popup it will give problem....me not expecting the exact code....if any one give information regarding how to refresh captcha image without reloading the whole page,,,,it will be usefull for me.....

Member 9155255 10-Apr-13 2:01am

i got the answer...thank u for ur suggestion.....

Sergey Alexandrovich Kryukov 10-Apr-13 9:49am

Great; you are welcome.
Will you accept the answer formally (green button)?
—SA

sharmayatin489 · Answer 2 · 2015-02-09T00:36:00

In Page_Load

protected void Page_Load(object sender, EventArgs e)
{
Bitmap obj = new System.Drawing.Bitmap(150, 50);
Graphics objGraphics = System.Drawing.Graphics.FromImage(obj);
objGraphics.Clear(Color.LightGray);
objGraphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;

Font objFont = new Font("Arial", 25, FontStyle.Italic | FontStyle.Strikeout);

Random r = new Random();
int startIndex = r.Next(1, 5);
int length = r.Next(4, 7);

String randomStr = Guid.NewGuid().ToString().Replace("-", "0").Substring(startIndex, length);

Session.Add("randomStr", randomStr);

objGraphics.DrawString(randomStr, objFont, Brushes.DodgerBlue, 5, 5);

Response.ContentType = "image/GIF";
obj.Save(Response.OutputStream, ImageFormat.Gif);

objFont.Dispose();
objGraphics.Dispose();
objBMP.Dispose();
}

And in other Page

TAke One Button, Image Control And one textbox
pu this below code under image control

img height="30" alt="Captcha" src="Test.aspx" style="width: 99px" />

put this below code under button click

protected void Button1_Click(object sender, EventArgs e)
{

if (TextBox1.Text.ToString() == Session["randomStr"].ToString())
{
Label1.Text = "Your Form is submitted";
}
else
{
Label1.Text = "Please enter input correctly";
}
txtTest.Text = string.Empty;
txtTest.Focus();

}