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Old September 19th, 2004, 11:39 PM
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Default Can't fire button event more than 1 time

Hi all,

I have a web form, and my page is coded in c#.
There is a button and a label in my webform, when I click on the button, the label should display +1.

My code as below:

protected void Button_Submit_OnClick (Object Src, EventArgs E) {
        Label1.Text = "Total: " + (x++);
}

x is public variable in the page. The problem is this event only fire at the first time...and seems not firing at all at the second time.

Any clue? :)

Thanks!

regards,
vic

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Old September 20th, 2004, 08:16 PM
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Hey,

You should be able to. It may actually not be retaining the total value... Are you storing the public variable x in the session or cache, and reloading it? After the page completely loads, the Unload event runs and all variables/objects are destroyed.

Brian
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Old September 21st, 2004, 09:24 PM
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Hi bmains,

Thanks for the reply, I tried ViewState["xx"], and it can't work, simply having syntax error.
Anyway I solved the problem by declaring the static variable.

However, new problem arise, the static variable remain static when I come back to the same page with other refference id, it shall be cleared and reset... any clue on that? :)

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Old September 22nd, 2004, 07:40 AM
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Hey,

Web is a disconnected environment. You need to store the value in the viewstate or cache. When a page finishes loading, all objects and variables (even static) are destroyed. The only way to persist these is through viewstate, session, application, or cache.

When dealing with the viewstate, make sure you assign a value to the key first before retrieving the value; otherwise, you are likely to get an error:

Page_Load {
//Do it here because viewstate entry must exist before being used
ViewState["x"] = 0;
}

Brian
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Old September 22nd, 2004, 07:45 AM
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Pages are instanciated and destroyed on each request. There is a classic pattern you can follow. Declare a property like this

int X
{
 get {
   if(ViewState["KEEPIT"] == null) { return X = 0; }
 else { return (int) ViewState["KEEPIT"]; }
}
set
{
  ViewState["KEEPIT"] = value;
}
}

I recommend you read a good book on ASP.net. You can going to hit pbs of this nature if you do not have some idea on the working of ASP.Net

Cheers

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