Confusion Over Postback, ViewState and Dynamically Added Controls

[Christian Nunciato]

Hi there:

I've checked the forums, but haven't found a situation addressing my
specific problem. Here's the deal:

I've got a Web Form containing two Panel controls. One displays search
results in a DataList comprised mainly of LinkButtons. The other's basically
empty; it's intended to handle a collection of dynamically added controls.

When the user clicks a LinkButton from within the first Panel control, I
want to be able to take the argument passed by that click and add, to the
second Panel control, an IFRAME tag with a reference to load from a URL based
on what the user clicked. This panel should be able to contain one 'n'
IFRAME tags.

The problem I'm having is that with each PostBack, the Panel that's supposed
to contain the "Controls.Add"-ed IFRAME tags only contains the one requested
by the most recent PostBack. Instead of creating the running, cumulative
collection of IFRAMEs with each LinkButton click that I'm looking for, the
Panel dumps everything and starts over with what was just requested.

I understand this probably has something to do with Page.Load and ViewState,
but I'm unclear as to how to address it specifically. Please help!

Thanks much,
Chris

[Brock Allen]

I posted a sample a while back on how to do this:

http://groups-beta.google.com/group/...717a97bd32c450

It's not doing exactly what you want, but the main thing is that you need
to recreate the controls upon every postback.

-Brock
DevelopMentor
http://staff.develop.com/ballen

Hi there:

I've checked the forums, but haven't found a situation addressing my
specific problem. Here's the deal:

I've got a Web Form containing two Panel controls. One displays
search results in a DataList comprised mainly of LinkButtons. The
other's basically empty; it's intended to handle a collection of
dynamically added controls.

When the user clicks a LinkButton from within the first Panel control,
I want to be able to take the argument passed by that click and add,
to the second Panel control, an IFRAME tag with a reference to load
from a URL based on what the user clicked. This panel should be able
to contain one 'n' IFRAME tags.

The problem I'm having is that with each PostBack, the Panel that's
supposed to contain the "Controls.Add"-ed IFRAME tags only contains
the one requested by the most recent PostBack. Instead of creating
the running, cumulative collection of IFRAMEs with each LinkButton
click that I'm looking for, the Panel dumps everything and starts over
with what was just requested.

I understand this probably has something to do with Page.Load and
ViewState, but I'm unclear as to how to address it specifically.
Please help!

Thanks much,
Chris