Dynamically created controls are wiped out on button click

Question

I have webform where a set of controls are generated in a Panel control during a SelectedIndexChanged event of a dropdown. That all works fine.

However, when I enter

Answer 1

This is one of those areas where the attempt to make Webforms look like Winforms fails.

With Webforms, you need to do the whole dance of when to create controls. I believe all your controls will need to be recreated by some time around the end of PageLoad. There might be an event or two after page load that you can use, but generally speaking PageLoad is a safe time to create controls.

Essentially the controls need to be created before ASP.NET populates them with data from ViewState/Browser.