This whole thing started out simple. All I wanted to do was pass a single variable back and forth between two pages in an admin section of a website using cross page postback. Were it not for my use of a master page I would not be writing about this. Without a master all you need to use is find control. However, with a master page things get more complicated. I’ll not go into it more than to say you need to find the control via the clientID and you need to somehow get that id in ways that I consider prone to error. Therefore I opted for strong typing of the previous page. This nailed me with another issue.
