Why is PreRequestHandlerExecute not called after postback redirect?

We have standard ASP.net behavior: when a button is pressed on a page, the brows开发者_运维百科er submits back to that page, and then the user is redirected with a 301 to the next page.

After the button is pressed, I see PreRequestHandlerExecute being called for the original page, but after the 301 redirect, the new page is displayed without PreRequestHandlerExecute being called again.

Shouldn't PreRequestHandlerExecute be called when the browser requested the second page after the redirect? Am I missing something?