Viewing the contents of Previous Page using ASP

**DrBunchman** · Apr 22 '08, 08:31 AM

Hi Vini171285,

Using session variables to retain the values of your controls is a valid and well accepted method. Some people would argue that it would be better to pass the values as hidden fields through a form or the querystring but as long as it works for you I think it's fine.

Can you print the code you're trying to use to set the value of your listbox with a session variable. There's no reason why it shouldn't work so it's probably just a little bug.

Dr B

**Vini171285** · Apr 22 '08, 09:58 AM

Re:

Hi, DrBunchman

Code:

 
Global.asa
<script language=vbscript runat=server>
Sub Session_onStart()
	Session("name")=""
	Session("pwd")=""
	Session("age")=""
End Sub
 
Sub Session_onEnd
	Session("name")=""
	Session("pwd")=""
	Session("age")=""
End Sub
</script>
 
 
z1.asp
<HTML>
<BODY>
<form method=post action="z2.asp">
Name:<input type=text name=name value=<%=Session("name")%>><BR>
Password:<input type=password name=pwd >
<BR>
Age:<select name=age>
		<option value=1>1 to 10
		<option value=10>11 to 20
		<option value=20>21 to 30
	</select>
<input type=submit>
</form>
</BODY>
</HTML>
 
 
 
z2.asp
<%@ language=VBScript%>
<% option explicit%>
<html>
<body>
<%
Session("name")=Request.Form("name")
Session("pwd")=Request.Form("pwd")
Session("age")=Request.Form("age")
Session.TimeOut=1
Response.Redirect "z3.asp"
%>
</body>
</html>
 
 
 
z3.asp
<html>
<body>
<form method=post action="z1.asp">
Hello<BR>
<BR>
<a href="z1.asp">back</a>
<input type=submit>
</form>
</body>
</html>

This is my code.Its just an example..
actual code is very big,in which we are retrieving data from database for listboxes..
and in our project there are 4 pages containing near about 86-87 listboxes..
So ,is Session still appropriate??

Everything is working properly with text box..
but in the case of list box,instead of printing the selected content, listbox is loaded as it is,and the selected value is lost..
What can be done in this situation??

Thanx

**DrBunchman** · Apr 22 '08, 10:46 AM

As I have said the question of whether you should use session variables in this situation is one that divides opinion. There is an article here that outlines some of the pros & cons of using them and I think you'll have to make up your own mind based on your circumstances.

To get your list box to maintain it's state you can use the following example:

Code:

 <select name=age> 
<option value=1 <% If Session("age") = 1 Then Response.Write(" selected ") End If %>>1 to 10</option>
<option value=10 <% If Session("age") = 10 Then Response.Write(" selected ") End If %>>11 to 20</option>
<option value=20<% If Session("age") = 20 Then Response.Write(" selected ") End If %> >21 to 30</option>
</select>

Let me know how you get on.

Hope this helps,

Dr B

**jeffstl** · Apr 22 '08, 07:18 PM

Originally posted by Vini171285

Hi..

I want to view the contents of previous page,but when i move from second page to first page,it is reloaded and the selected contents are lost..
So what should i do so that when i move from 2nd page to 1st page,all selected contents should remain same..
Actually i tried using session and it is working,but it doesn't work with listboxes.
Is it a good practice to use Session variables.

Thanx

Session variables was going to be my answer for you. Yes session variables are good practice as long as you clear them when you are done with them.

What do you mean by the session variable doesnt work with the listbox? If you are allowing multiple selections of the list box you need to set up an array variable to handle that probably to hold all the users selections.

Otherwise the only way to pass data is to use the querystring which if you have alot of it can get very tedius. (myaddress.asp? data1=this&data 2=this). Or you can use hidden text box fields and get the data with request.form on the next page, etc.

**Vini171285** · Apr 23 '08, 04:15 AM

hi..
This is my code when trying to fill list box from database..
Error is in IF stmt(Type mismatch)..
Can u Help..
Code:

Code:

 <%@ language=VBScript%> 
<% option explicit %>
<!--#include virtual="/adovbs.inc"-->
<HTML>
<BODY>
<form method=post action="z2.asp">
Name:<input type=text name=name value=<%=Session("name")%>><BR>
Password:<input type=password name=pwd >
<BR>
Age:<select name=age>
<%
	Dim objConn
	Set objConn=Server.CreateObject("ADODB.Connection")
	objConn.ConnectionString="DSN=Info.dsn;uid=vini;pwd=vini"
	objConn.Open
 
	Dim sql
	sql="SELECT * FROM age"
 
	Dim objRS
	Set objRS=Server.CreateObject("ADODB.Recordset")
	objRS.Open sql,objConn
 
	Do while not objRS.EOF
		Response.Write "<option value='" & objRS("num") & "'"
		If Session("age")=objRS("num") Then
			Response.Write "selected"
		End If
		Response.Write ">"
		Response.Write objRS("age")
		objRS.MoveNext
	Loop
 
	objRS.Close
	Set objRS=Nothing
 
	objConn.Close
	Set objConn=Nothing
%>
</select>
 
<input type=submit>
</form>
</BODY>
</HTML>

**DrBunchman** · Apr 23 '08, 08:52 AM

You could try using

Code:

If Session("age") = CInt(objRS("num"))

to cast your record item to a type of integer while comparing it.

Any good?

Dr B

**Vini171285** · Apr 23 '08, 11:05 AM

Hi..
Its not working
any other suggestion..

**DrBunchman** · Apr 23 '08, 11:21 AM

Hmm....

What about if you do something like:

Code:

 Dim num 
num = objRS("num")
 
If Session("age") = num Then

Dr B

**jeffstl** · Apr 23 '08, 06:15 PM

Originally posted by Vini171285

Hi..
Its not working
any other suggestion..

When you say its not working does that mean you are still getting the type mismatch error or something else? Also which line are you getting that error on?

Since I don't know whats in your database I am going to assume one of the problems may be checking for null?

As far as casting the data type the only time that matters in asp is when your sending the value to a database or a vb class. All variables in asp are automatically variants.

Lastly another thing I noticed was that when you cancatonate (like below) you are using the single quotes. That is for SQL, not for strings. So I removed them for this example. That could be your problem also.

One more thing too and maybe I'm just missing something here...but you dont have the <select> tag before you start writing your <option>?
Oh yeah...a close option tag you were missing too </option> at the end

[code=asp]
'need <select> tag??

Do while not objRS.EOF
If Not IsNull(ObjRS("n um")) then
Response.Write "<option value=" & objRS("num") & ""
If Session("age")= objRS("num") Then
Response.Write " selected" 'added a space to seperate
End If
else
Response.Write "<option value=0"
end if

Response.Write ">"
Response.Write objRS("age")
'then you need a close tag here
response.write "</option>"
objRS.MoveNext
Loop
'need an </select> tag??

[/code]

**jeffstl** · Apr 23 '08, 09:07 PM

OK I see your <select> tags now, but you are missing the </option>.
Sorry

**Vini171285** · Apr 24 '08, 04:05 AM

Originally posted by DrBunchman

Hmm....

What about if you do something like:

Code:

 Dim num 
num = objRS("num")
 
If Session("age") = num Then

Dr B

We have tried this also,but its still not working...Its not giving any error,but selected value is lost,list box regains its default value as it is....

**Vini171285** · Apr 24 '08, 04:07 AM

This is changed code,but it has the same problem of not retaining values between pages...
It is giving no error....

Code:

 
Code:
<%@ language=VBScript%>
<% option explicit %>
<!--#include virtual="/adovbs.inc"-->
<HTML>
<BODY>
<form method=post action="z2.asp">
Name:<input type=text name=name value=<%=Session("name")%>><BR>
Password:<input type=password name=pwd>
<BR>
Age:<select name=age>
<%
	Dim objConn
	Set objConn=Server.CreateObject("ADODB.Connection")
	objConn.ConnectionString="DSN=Info.dsn;uid=vini;pwd=vini"
	objConn.Open
 
	Dim sql
	sql="SELECT * FROM age"
 
	Dim objRS
	Set objRS=Server.CreateObject("ADODB.Recordset")
	objRS.Open sql,objConn
 
	Do while not objRS.EOF
		If Session("age")=CInt(objRS("num")) Then
			Response.Write "<option value='" & objRS("num") & "' selected>"
		Else
			Response.Write "<option value='" & objRS("num") & "'>"
		End If
		Response.Write objRS("age") & "</option>"
		objRS.MoveNext
	Loop
 
	objRS.Close
	Set objRS=Nothing
 
	objConn.Close
	Set objConn=Nothing
%>
</select>
 
<input type=submit>
</form>
</BODY>
</HTML>

**jeffstl** · Apr 24 '08, 02:47 PM

You are still not cancatonating correctly in your strings.

You don't use single quotes for strings, only SQL.

WRONG:
[code=asp]
Do while not objRS.EOF
If Session("age")= CInt(objRS("num ")) Then
Response.Write "<option value='" & objRS("num") & "' selected>"
Else
Response.Write "<option value='" & objRS("num") & "'>"
End If
Response.Write objRS("age") & "</option>"
objRS.MoveNext
Loop
[/code]

RIGHT:
[code=asp]
Do while not objRS.EOF
If Session("age")= CInt(objRS("num ")) Then
Response.Write "<option value=" & objRS("num") & " selected>"
Else
Response.Write "<option value=" & objRS("num") & ">"
End If
Response.Write objRS("age") & "</option>"
objRS.MoveNext
Loop
[/code]

As far as retaining your values, there is no reason that Session("var") should not work.

Try bringing stuff back to basics to find out why your losing the value. Do some response.write' s on your session variables for testing. I would recommend doing a response.write on your Session("age") before your IF statement so you can see whats in there.

If possible just start from scratch for testing purposes just to work with some session variables.

Or do a step through if you have MS Studio and a localhost) and try to determine at what point the value is being lost.

Don't forget if you need to you can also work with hidden text fields and simply get the value with request.form.

**DrBunchman** · Apr 24 '08, 05:49 PM

Originally posted by jeffstl

You are still not cancatonating correctly in your strings.

You don't use single quotes for strings, only SQL.

There's nothing wrong with using single quotes inside a string to delimit your property values.

Code:

Response.Write "<img src='foo.gif' alt='bar' />"

generates perfectly good mark up and as far as I know this would never generate an error.

Unless there's a reason you think otherwise and I'm completely wrong ;-)

Dr B

Viewing the contents of Previous Page using ASP

Viewing the contents of Previous Page using ASP

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