Tricky postback

[Matt]

Hello,

In an aspx page i have webform with some textboxes and a simple
button. When the button is clicked, there is a postback and then the
code in the click event of the button is executed.

However in this code (click event of the button), i'm processing an
online payment, which takes about 5 seconds. While waiting for the
payment to be processed, the user can click again on the button, and
this is what i want to block. I want to disable the button once
clicked, and then execute the code for the web payment.

However when we disable a button in the Load event, the page is only
displayed after the Unload event, so the button still appears as
enabled when executing the code in the click event of the button.

I tried to call a javascript function on the onclick of the button to
disable it but i get a compilation error at runtime. Is there a way to
disable a webform button when clicked, then execute the code on the
Click event of this button? The button needs to appear as disabled on
the page before the code is executed.

Thanks for any help!

 

[Steve C. Orr, MCSD]

Even if you disable the button you'll likely have the same problem if the
person refreshes their browser.
To solve this problem, you can generate a unique id for that web page
instance.
If you detect that unique id being posted more than once, then ignore the
subsequent reposts.
Here's a good article on the subject:
http://www.aspnetpro.com/features/2003/09/asp200309de_f/asp200309de_f.asp

 

[eruess]

I had this problem with an authentication page where authenticating the user
took a few seconds and I didn't want them to keep clicking. Basically you
have to do 2 things with 1 click... something to visually alter the screen,
and then handle the actual click in your c/vb.net code.

Make a javascript block to do whatever you need to do on the client when
they click the button. In the example, js renders the button "hidden".

<Script Language="JavaScript">
function clickHandler()
{
frmLogin.btnLogin.style.visibility = 'hidden';
}
</Script>

In my html, here's the submit button the user clicks:

<form ID="frmLogin" runat="server">
<asp:Button ID="btnLogin" class="button" text="Log In"
onclick="Login_Click" Runat="server" />
</form>

Now in Sub page_load, you need a call to RegisterOnSubmitStatement. This,
afaik, tells asp.net to run the js function specified then handle the click
event in asp.net:

Sub Page_Load(s As Object, e As EventArgs)
RegisterOnSubmitStatement("submit", "clickHandler();")
'...code

So when the user clicks btnLogin on my form, RegisterOnSubmitStatement calls
the javascript that hides the button, and then my vb.net routine called
"Login_Click" would run. 2 routines for the price of 1 click.

You can augment the functionality of the clickHandler(); js routine to
display a please wait message, etc. Just don't damage the integrity of the
button object from the js code or the codebehind handling the button event
may fail. For example, I believe this code breaks if you 'disable' the
button or remove it completely. Hiding it is safe, and certainly renders
the button un-clickable for the remainder of the page life.

HTH

 

[MS News \(MS ILM\)]

I tried to run your code and I am getting errors
'ASP.WebForm1_aspx' does not contain a definition for 'Login_Click'

???

 

[MS News \(MS ILM\)]

Got it. Sorry I did not provide the Login_Click Sub in code Behind

 

[eruess]

Login_Click is the name of a Sub in my code. You'll need to modify my post
to have it function within your own project.
code in the click event of the button is executed.
However in this code (click event of the button), i'm processing an
online payment, which takes about 5 seconds.<<

So then instead of trying to call my Login_Click (which doesn't exist in
your application) you'll want to call whatever sub does what you described
in the above paragraph... 'Button1_Click' or whatever you / vs.net may have
named it.

Bear in mind with my project, Login_Click did not Handle any control events
(such as clicking), and AutoEventWireUp was False. I have not tested this
thing in a situation where I'm directly calling the sub that also handles
the button's click.

 

[Matt]

Thanks, this is exactly what i was looking for! I also added some code
in the javascript function to show a layer, containing a message and
an animated gif acting like a progress bar.

However the gif stops when the web payment code is executed, so the
gif is useless. A flash animation works but i don't want to use flash
in this project.

But the essential is that it works, thanks!

 

[MS News \(MS ILM\)]

Thank you, that is great

Login_Click is the name of a Sub in my code. You'll need to modify my post
to have it function within your own project.

code in the click event of the button is executed.
However in this code (click event of the button), i'm processing an
online payment, which takes about 5 seconds.<<

So then instead of trying to call my Login_Click (which doesn't exist in
your application) you'll want to call whatever sub does what you described
in the above paragraph... 'Button1_Click' or whatever you / vs.net may have
named it.

Bear in mind with my project, Login_Click did not Handle any control events
(such as clicking), and AutoEventWireUp was False. I have not tested this
thing in a situation where I'm directly calling the sub that also handles
the button's click.

 

[sivanekar]

Hi All..
I hav same problem.. Im using d same javascript its working fine. But whn im using master page i cont find tht control(button). so pls help me..

Thanks in Advance