Updatepanel not updating
I'm guessing you're having problems with bttn Edit being clicked and not causing your Update Panel to refresh, even tho you have an explicitly defined trigger.
If that's the case, you're problem could be revolving around the fact that you do not actually have a server side click event defined for bttn Edit.
NET AJAX server controls: the Script Manager control, the Update Panel control, and the Timer control.
While I don't know exactly what was stopping it from working, i suspect it may have been caused by the following attributes set on buttons in other parts of the form: Adding that back in to my working form causes the update Panel to break..
but removing it from my original broken form does not fix it, so perhaps there was something else in there too.
If you try to work with one of these controls, and your website doesn't contain the required web.config file, errors appear in the This walkthrough introduced the basic concepts of using a Timer control and an Update Panel control to enable partial-page updates.
You must add a Script Manager control to any page that contains an Update Panel control or Timer control.