How can I intercept and correct keypresses at a low level?

I keep typing "t eh" instead of " the" which is, of course, annoying in the amount of time it takes me to correct myself.

The obvious answer is "Learn to type, noob!" or at least to type more slowly and/or more correctly. This error is frighteningly consistent so it appears I've trained my muscle memory for that pattern already.

But I'm wondering if it's possible to write a small, windows portable script or application that, when it detects the incorrect sequence, backspaces and corrects it automatically at a layer where it would apply to any keyboard input.

Does C# have access to that layer of the OS that intercepts keypresses systemwide?
Will I run into UAC issues with Vista?
Am I re-inventing the wheel (ie, are there open source tools I can modify or use out of the box)?

In DOS this sort of thing was quite easy and one could make TSRs (Terminate and Stay Resident) programs that would, for instance, give you a calculator onscreen with a special keypress. Not to mention the many, many practical joke programs based on this concept (dial "M" for monster!)...

I would, of course, never suggest such a utility could be used that way for co-workers...

-Adam

Solution

I suggest AutoHotKey. If you've never used it before, have a quick read of the tutorial: http://www.autohotkey.com/docs/Tutorial.htm

The feature you are looking for is called "hotstrings." http://www.autohotkey.com/docs/Hotstrings.htm

In your case, your script would look something like:

::teh::the

That's it! Add other things you want corrected on additional lines. AutoHotkey scripts can be compiled so you don't have to install AutoHotKey on all of your machines.

It's a very cool program. It's primary use (for making custom hotkeys) rocks! These scripts are system wide so you'll also probably want to make a hotkey to be able to turn them off too!

EDIT: In a comment, it was mentioned that he actually types "t eh" (with a space in it) and I wondered if something additional would be needed for it to work. I just tested it and it works fine. Just install autohotkey, and create a file with the .AHK extension. In that file put in the following line

::t eh::the

and save the file. Then double-click on the AHK file to load AutoHotKey with your script (you'll see a green square in your system tray to let you know it is running). It should work fine!