Why session variables are not passed between pages?

[temp1213]

I have two ASP .NET web forms A and B. A is a web form that geneates a binary graph and create some session variables before generate the graph. B is the display page which calls the A and display the graph generated by A. The code in B is like this:

<img width="" height="" src="graph.aspx?a=3&b=4">
<% Response.write(Session("numOfBars")) %>

graph.aspx is the file name of A, and "numOfBars" is a session variable created in A just before the graph is generated. My problem is the graph is displayed corretly in B, but B cannot get any session variable created by A. It seemed session variables are not passed to B at all. However, if I use
Response.redirect(B) in A, then I can print all session variables created by A. How can I pass session variables created in A to B without any redirection. Put it in another way, if B just calls A, why B can't see the session variable created by A? How can I pass them from A to B in this situation?

I tried all best but still couldn't solve the problem. Any suggestion or reference link is greatly appreciated.

-John

[bharathreddy]

Dear John,

Here one thing that we should note is, in B you are showing A (that is graph).
So first the B Page_Load event will take place then A Page_Load. B will load first then A will be loaded so u cant get the session variables in B.

Summary:
These session variables in A are assigned after B Page_Load.


with Regs
Bharath Reddy
[phone]
India

[temp1213]

Bharath,

Thank you very much for your reply. I'm newbie for asp .net. In my case, how can I get session variables created in A? or, how can I force a page_load event of A to occur before B's page_load event? Is there other way to get the session variables without a page_load event? Thanks in advance for further suggestion.

-John

[bharathreddy]

Dear John,

I dont know the answer but i can sujest u to go for other options like save the data which u want to store in the sessions in an xml file and read that file when u want or use database for the same.

But even this will not work in your case because B Page_Load and UnLoad events will fire first before A's Page_Load fires. (Simple reason behind this is we cant read a value before it is set).
I got the same problem I took frames instead of img tag. The problem solved. In first frame keep the A page and in the second frame keep B. In this case A will be loaded first and then B so u will get the session values set in page A.

Note:
-------
Passing values from one page to another is by : session, cookies , querystring and database/xml. Using any of these we cant achive your case. So i think u need to go with frames.

Bharath Reddy

[scripto]

start with the easy things first - check your browser settings - you must accept cookies for Session variables to work. Also if you touched your web config file, make sure accept cookies is turned on.

Give that a try first.