ASP.NET

Re: value is not getting in dropdown after a button click

9-Jun-09 21:36

Not a chance in hell. If it gets lost, it will still get lost on an autopostback

Christian Graus

Driven to the arms of OSX by Vista.

"! i don't exactly like or do programming and it only gives me a headache." - spotted in VB forums.

I can do things with my brain that I can't even google. I can flex the front part of my brain instantly anytime I want. It can be exhausting and it even causes me vision problems for some reason. - CaptainSeeSharp

Christian Graus9-Jun-09 21:20

Re: value is not getting in dropdown after a button click

9-Jun-09 21:20

Odds are good that you're binding to your data source every time. This will clear the selection. So, bind your drop down to your data source in an if (!IsPostback) block.

Abhijit Jana9-Jun-09 21:23

Abhijit Jana

9-Jun-09 21:23

anbusenthil wrote:
here while saving or inserting a record
i am not getting any values in dropdown which i hav selected

I Guess, this is due to postback while storing and loading data from database. Unless you post the relevant code its difficult to say.

cheers,
Abhijit
CodeProject MVP
Web Site:abhijitjana.net

Static Varible Sharing Problem

Shivan Nandan9-Jun-09 21:03

Shivan Nandan

9-Jun-09 21:03

Hai Friends

I have declared a variable outside all the function in an aspx.cs page, like

public partial class StaticVar : System.Web.UI.Page
 {

    static int a;

    protected void Page_Load(object sender, EventArgs e)
    {

        Response.Write(a.ToString());
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        a = 50;
        Response.Write("set 50, a= " + a.ToString());
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        a = 60;
        Response.Write("set 60, a= " + a.ToString());
    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        Response.Write("a= " + a.ToString());
    }
}

The problem is that when more than one user access this page and modifies the variable a, all the users gets the new value for a,
i.e., they loose the value what they had set for a. They get the value that is been set by the last user.

If I remove 'Static' from its declaration, then its value is not available to other functions.

How to solve this problem.
Please help me.

Shivanandan C V

Christian Graus9-Jun-09 21:11

9-Jun-09 21:11

Buy a basic book on ASP.NET and read it. Actually, I suspect your issue is that you don't understand ASP.NET. Static works just as you are seeing, and non static only exists for the lifecycle of one page. Therefore, you need to store values in something persistent, such as the session, or if it's all in one page, viewstate.

saanj9-Jun-09 21:13

9-Jun-09 21:13

There is no need to declare it static if you are declaring it as class level variable. As a class level variable, it's value should be accessible in all methods inside that class.

Regards
Saanj

Either you love IT or leave IT...

Christian Graus9-Jun-09 21:21

9-Jun-09 21:21

But not between postbacks.

Shivan Nandan9-Jun-09 21:25

Shivan Nandan

9-Jun-09 21:25

If I don't declare it as Static, then its value is retained only in the function in which it is assigned. In other function its value becomes 0. Please check my code without Static identifier.

Shivanandan C V

Colin Angus Mackay9-Jun-09 21:31

Colin Angus Mackay

9-Jun-09 21:31

Shivan Nandan wrote:
If I don't declare it as Static, then its value is retained only in the function in which it is assigned. In other function its value becomes 0. Please check my code without Static identifier.

The issue is that without the static the variable is only available for that one instance of the page. Every time you visit the page you get a new instance of the page so the variable is set back to what it started as.

Your mental model is that when a user gets a page they retain that page object for the duration of their session. They don't. That would place an huge strain on the server to maintain all that for all users.

A page will be destroyed soon after it is rendered - along with all variables on it.

Man who stand on hill with mouth open wait long time for roast duck to drop in

saanj9-Jun-09 21:31

9-Jun-09 21:31

Use Session variable.

Regards
Saanj

Either you love IT or leave IT...

Re: Static Varible Sharing Problem [modified]

Colin Angus Mackay9-Jun-09 21:24

Colin Angus Mackay

9-Jun-09 21:24

Shivan Nandan wrote:
The problem is that when more than one user access this page and modifies the variable a, all the users gets the new value for a,
i.e., they loose the value what they had set for a. They get the value that is been set by the last user.

That is the correct functionality. ASP.NET applications are multi-user applications. static variables are global for the entire application. If you set it to some value then all users will see that value.

Shivan Nandan wrote:
If I remove 'Static' from its declaration, then its value is not available to other functions.

Incorrect. Its value is available to the methods in the class. This time however, the value only lasts as long as the object it is in lasts (in this case the object is the one representing your page).

Shivan Nandan wrote:
How to solve this problem.

Looking at your sample code, you expect the value to hang around for postbacks. That isn't going to happen. The page object (along with your variable) will exist for as long as it takes to process and render the page. The page object is them discarded (along with your variable).

So, basically, you need some mechanism to store the value between postbacks. You can store the value in the page itself (a hidden field, or add it to the viewstate). You could store it in the session. You could create your own mechanism. It is up to you.

Ultimately, you need ot read a book on how ASP.NET works, and especially how the page lifecycle works as this leaky abstraction trips up many people. In other words HTTP is stateless, but ASP.NET tries to provide a stateful framework, and sometimes it just doesn't work they way you'd expect. So you have to go and read some stuff about the page lifecycle to understand what is going on.

Man who stand on hill with mouth open wait long time for roast duck to drop in

Shivan Nandan9-Jun-09 21:38

Shivan Nandan

9-Jun-09 21:38

Thank you very much for helping me...

Shivanandan C V

modified on Wednesday, June 10, 2009 4:17 AM

How To Log when user clicks on the cross button through Ajax

shimona 29-Jun-09 20:54

shimona 2

9-Jun-09 20:54

I am handling one project in asp.net.Now I want to update my sql database when anyone leave the domain. So I need to call a stored Procedure when user leave page. And I can do it very easily if user click on logout button. But the problem arises when anyone just close the browser (by clicking cross button) or when he navigate away to another page (typing another address in address bar). Some ppl said that this can be done with Ajax script. Anyone please provide some coding for this?

Regards,
Shimona

Re: How To Log when user clicks on the cross button through Ajax

saanj9-Jun-09 21:05

Re: How To Log when user clicks on the cross button through Ajax

9-Jun-09 21:05

Try the following link:

http://www.developerfusion.com/forum/thread/24783/[^]

Regards
Saanj

Either you love IT or leave IT...

Sujay chakraborty9-Jun-09 21:17

Sujay chakraborty

9-Jun-09 21:17

hey shimona 2,

The issue can be dealed with javascript, Please go through the following html code that captures the close button click event

<html>
<head>
<script language="javascript" type="text/javascript">
window.onbeforeunload = myunload;
function myunload()
{
	alert('Window is closing!!');
}
</script>
</head>
<body>
</body>
</html>

Hope this helps

Regards

Manipulating XML file using GridView and XmlDataSource

Sujay chakraborty9-Jun-09 20:33

Sujay chakraborty

9-Jun-09 20:33

Hello everyone,

I am designing one simple application where i want to insert, update and delete a XML file using DataGrid and XmlDataSource. I am done with adding and deleting code, but one thing i am stuck with is i cannot view the updated or deleted data back to the grid view after the page gets post back when we click the add or delete button although i have check the xml file and the data gets added and deleted respectively.

I have tried with DataGrid1.DataBind() method but its not working. To add and delete data programatically i have to implement e.Cancel = true; in the DataGrid1_RowDeleting event(without this it won't work). please tell me a way to dynamically reflect the updated data back to the grid view

Waiting for a quick response. Thanks in advance

Regards

Re: Manipulating XML file using GridView and XmlDataSource

Abhijit Jana9-Jun-09 21:11

Abhijit Jana

9-Jun-09 21:11

Where did you load the data? Can you please put the GridView Data Load Code ? Did you check the Page.ISPostback while loading the data on gridview ?

cheers,
Abhijit
CodeProject MVP
Web Site:abhijitjana.net

Re: Manipulating XML file using GridView and XmlDataSource

Sujay chakraborty9-Jun-09 21:21

Sujay chakraborty

9-Jun-09 21:21

Thanks for replying.
Actually i have used an XmlDataSource and set its DataFile property to the xml file and set the DataGird's DataSourceID property to the XmlDataSource. I have given the XPath rules to the grid view colomns to display the data.

Well m sure i have done some mistake but where i have done it i couldn't figure it out. Please help

Regards

Re: Manipulating XML file using GridView and XmlDataSource

chaitanya2313-Jan-10 20:15

chaitanya231

3-Jan-10 20:15

hi..

even i am facing the same problem. can some one pls help me soon.

i have a XMLDataSource for which i mentioned the datafile to 'MyXml'.

In my page i have a textbox and a button 'add' for adding the text to the xml and display the same in the datagrid.

but wen i click that add button the data is getting updated in xml file and i can see that, but in the datagrid it is not getting updated.

pls help soon.thanx in advance.

configuration error...

RajpootRohan9-Jun-09 20:16

RajpootRohan

9-Jun-09 20:16

Hi to all,

I need your assistance. Please help me on this.
I published my website but when I tried to browse, it is giving the following error:

Server Error in '/' Application.
Configuration Error
Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

Source Error:

Line 38: ASP.NET to identify an incoming user.
Line 39: -->
Line 40: <authentication mode="Windows">
Line 41:
Line 42: </authentication>

Source File: e:\inetpub\host134\vicinternational\vicinternational.vic.edu.au\www\vic\web.config Line: 40

Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.210

what to do? PLease tell me. Its very urgent.

cheers,
sneha

Abhijit Jana9-Jun-09 20:21

Abhijit Jana

9-Jun-09 20:21

sneha Choudhary wrote:
I published my website but when I tried to browse, it is giving the following error:

After publishing the web site what you did? Did you create the Virtual Directory in IIS? Did you set the ASP.NET Framework version of the Virtual directory?

cheers,
Abhijit
CodeProject MVP
Web Site:abhijitjana.net

RajpootRohan9-Jun-09 20:30

RajpootRohan

9-Jun-09 20:30

Hi,

Thanks for replying. Yes created a virtual directory in IIS.
And I am using Visual Studio 2008 and

ASP.NET Framework version of the Virtual Directory is 2.0.50727.

Am I doing right?

cheers,
sneha

Christian Graus9-Jun-09 20:25

9-Jun-09 20:25

sneha Choudhary wrote:

what to do? PLease tell me. Its very urgent.

It can't possibly be, because the mistake you've made is both far to elementary for this task to have been trusted to you, if it's urgent, and, if it was urgent, you'd have googled the error message and got your answer.

RajpootRohan9-Jun-09 20:32

RajpootRohan

9-Jun-09 20:32

Hello Sir,

I googled a lot but from there I got the idea to configure the site to IIS. I did that.But again getting the same error.

cheers,
sneha

saanj9-Jun-09 20:26