PlaceHolder That Persists Its Children
I'm currently creating a wizard engine in ASP.NET that we can reuse. The data is saved in Sql Server tables and associated with users. Creating new wizards just involves setting up some new rows in the database and any custom UI you need. A big part of this that I needed was a PlaceHolder Control that didn't lose its children between postbacks. I have a UserControl for each step in the wizard and just flip them in and out when flipping through the steps.
Luckily, Google came to the rescue as always, because I knew I had heard of someone doing something like this. Unfortunately though, it took forever to find! Maybe this post will bring it up higher in Google so people can find it easier than I did.
Dynamic Control PlaceHolder by Denis Bauer