Removing session on button click event

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Hi all,

I have a serious bug. I have some dates that i maintain in a session from some page. dan on the page load of other page i use that session to fill the text box and below the texbox download button is there. The problem is that if the user changes the date in text box and than clicks on the download button for that date still the date that i am getting is which was in session. That is I am not able to change the dates once session has filled the text box. Although I am clearing the session and removing it on button click event still... Can u plzz tell me wat m missing ?
here is my code:-

C#

protected void btnDwnload_Click(object sender, EventArgs e)
    {
        Session["str_Single_Date"] = null;
        Session.Remove("str_Single_Date");

        Session["str_Single_Date"] = null;
        Session.Remove("str_Single_Date");

        
        string strData = txtDataType.Text;
        string strDataType = strData.ToString().ToUpperInvariant().Trim();
        DateTime From = Convert.ToDateTime(txtFrom.Text.Trim()); <--- here i m getting the same dates always
        DateTime To = Convert.ToDateTime(txtTo.Text.Trim());  <--- here i m getting the same dates always
        string strComb = txtCombi.Text;
        string strProd = txtProd.Text;
        string strHSCODE = txtHSCode.Text;
       

        int iResult = bl_Query_for_admin.Query_Data(strDataType, From, To,strHSCODE, strComb, strProd);
        if (iResult == 1)
        {
            lblMsg.Visible = false;
        }
        else
        {
            lblMsg.Visible = true;
            lblMsg.Text = "Invalid Query Formation Resulted Into No Data Generation !";
        }

    }

Posted 23-May-12 21:29pm

Taresh Uppal

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3 solutions

Solution 3

this is the syntax for removing session
Session.Remove("SessionName");

you fill the textbox data by session value

C#

protected void Page_Load(object sender, EventArgs e)
    {

// assign textbox value to session on postback 
if (IsPostBack)
        {
            Session["SessionName"] =TextBox1.text;
        }
/*
if is not post back and open first time page then assign textbox value from session
*/

if (!IsPostBack)
{
TextBox1.text=Session["SessionName"].ToString();
}

}

if you do code in page load event like i describe above than you don't need to remove session.

Posted 25-May-12 3:07am

Prosan

Solution 2

will anybody help me on this ?

Posted 24-May-12 21:12pm

Taresh Uppal

Comments

mr.priyank 25-May-12 3:20am

where are u assigning the value of textboxes from session?

Taresh Uppal 25-May-12 3:56am

on the page load but outside if(!ispostback)...

Taresh Uppal 25-May-12 3:57am

There is a reason for this coz next tym when the page loads then i dnt want all the fields to change ...i have datefrom and dateTo text boxes whose value i want to change as per user request...
if i kp the thngs in postback than on secnd tym load all the values go empty...:(

Prosan 26-May-12 6:16am

what's happen is your problem sort out or not. if not where you got stuck.

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OriginalGriff · Accepted Answer · 2012-05-23T21:38:00

Solution 1

Stop loading the textbox with the dates in your Page_load event except when IsPostBack[^] is false!

When your user presses a button, your application is started, and the Page Load event handler is called. If you do not check in the handler if this is a Postback, you load the values from the Session into the TextBox, and overwrite any values the user had entered. The Button Click event handler is then called, which reads the overwritten values from the text boxes.

So what it looks like is that the session values are not being deleted - they are, but just after you have used the values to overwrite the user input!

Posted 23-May-12 21:38pm

OriginalGriff

Comments

Taresh Uppal 24-May-12 4:06am

if i wont do it..than info will be missing..than how would text box be automatically populated the very first time when the user visits the page ?? I understand your point but doing it is the only way i guess...

OriginalGriff 24-May-12 4:11am

Trust me, it's the way things work. In your Load event handler, you need to check if this is a postback - if it is a postback then it's the first time load and you should use the session to load your boxes. If it isn't, then it's a load as a reposnse to user activity on the page and you shouldn't!

[edit]Typo: "isn't" twice, instead of "isn't" and "is" :O - OriginalGriff[/edit]
You need to look at how web pages work in a bit more detail, or this kind of thing is going to bite you repeatedly, and slow you down a lot! Web development is very, very different from desktop - there are at least two separate processing systems involved, instead of one and this means things work differently.

Taresh Uppal 24-May-12 5:02am

thanx a lot for your response... but when i am not loading the text boxes on page load..means (!ispostback)....coz when i do it ..than on button click when i try to retrieve the text box value it says it is not a valid date time string...:(

Taresh Uppal 24-May-12 5:18am

this happens on my page load from wher text box is populated very first tym:
if (!IsPostBack)
{
pn_Details_Particular_Query.Visible = false;
lblMsg.Visible = false;

}

if (Session["Client_Particular_Query_Details"] != null)
{
DataTable dtDetails = (DataTable)(Session["Client_Particular_Query_Details"]);
if((dtDetails != null)||(dtDetails.Rows.Count !=0))
{
fill_Query_fields_Particular_Query(dtDetails);
}

}

and the button coding i have shown u...please reply

OriginalGriff 24-May-12 5:40am

You need to extend the if condition to cover all of that code - at the moment it only covers two lines...

Taresh Uppal 24-May-12 5:50am

if I do that still once the button is clikced i get the same error that date time is nota valid string coming from the textbox.

OriginalGriff 24-May-12 6:04am

Then you need to add some debug code to report what the string is: look at what the string you are feeding to the Convert.ToDateTime method, and look at why it isn't valid. Get information - you can't solve problems by guesswork! :laugh:

Taresh Uppal 24-May-12 6:25am

on the button click event i have taken a variable
DateTime dtFrom = Convert.TodateTime(txtFrom.text);
Simple....during first time it feeds the thing correctly but after that when button click is reached it always takes the value that was in session for this textbox not the new value if user had entred in it. Moreover i m populating this textbox in page load but outside if(!ispostback)..coz using if(!isnot...) on button click it makes all the fields empty and txtdate gves wrong value...

OriginalGriff 24-May-12 6:36am

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// Fill Fields from Session
}
else
{
// Don't touch the damn fields at all.
}
}

Taresh Uppal 24-May-12 11:37am

i have already done this before posting quetion here...it always do one thing..when i click the dwnload button it gets d value from session again... is it possible just to use the session once first tym and after that removing it for the next postbacks...?

Nelek 25-May-12 15:53pm

Nice explanation