How to sort on keydown

[Admin]

Hello everyone. 

I wrote the following code: 

on keydown 
 show
field "MonthDropDown"
 sort items of field "MonthDropDown" by keydown
letter
end keydown

It's wrong. I know it's wrong. How do I make it
right? (I want the drop down list to end up on the letter of what the
user pressed on keydown, so if they pressed 'd' or 'D' I want "December"
to become highlighted.

Thanks everyone.

Mike