How to tell if a refresh came from a Timer (C#)

问题

I have a ton of update panels and such on my webform (which are created dynamically at runtime)

I am wanting to put a locking timer or something similar in my form also. My problem is this. When someone is typing into a text box, and the timer happens they lose part of their text and the control loses focus.

The reason this happens is because on post back some things are done and the screen is rebuilt and the current control panel is updated. The reason this happens is because the only things that would cause the page to get refreshed prior to this timer were Change events on the controls(in which things need to be checked and updated). So what I need is to know if this Lock Timer is what caused the refresh so that I don't rebuild the screen or touch anything else like that. I can't wait until it gets to the Tick event because by the time it's there the screen has already been rebuilt and messed up for the user.

Also, I can't use viewstate or any other magic, as the screen is rebuilt at Page_Init. I checked if sender would say the timer, but it only gives the current page..

So my question is this:

How do you tell if the reason a refresh happened is because of an update timer at Page_Init?