So I understand the basics of the prg pattern. But I haven't come across a technique for making arbitrary data available to the "get" instance of a page.
For example, I might want to display different feedback messages to the user depending on their action which initiated the PostBack.
What I've been doing is sending an identifier as a query string parameter. This works fine but it introduces bookmarking issues and doesn't seem like it would scale very well. What if I needed to send all of the ViewState?
Unfortunately, I'm tied to WebForms at the moment and haven't been able to convince my organization to migrate to mvc.