I have a date picker that I am trying to send a date to. I can figure it out when using current date. But if I want to send something that is not current date what format should I use? Example, if i want to send it a date of “01/04/2010” it does nothing.
set content of control "date_picker" of window "main" to current_date
I think this should do it:
set myDate to date "23/12/2012"
set content of control "Date Picker" of window "Main" to myDate
or just
set content of control "Date Picker" of window "Main" to (date "23/12/2012")
Hope it works,
ief2
EDIT: Just a reminder, if you compile your script, the string “23/12/2012” is going to change into something like this: date “zondag, 23 december 2012 00:00:00”. If you want to keep the original, define your date like this:
date ("23/12/2012" as string)
Hi,
the date picker expects a value of class date.
Consider that creating a date from a string depends on the international date format settings.
This works on an US system, but might give an unexpected result or throw an error on non-US systems
set d to "01/04/2010"
set AppleScriptDate to date d
Thanks StevenK, works great!
Who?? 
My bad lol
Thank you StefanK, you are the best!
BTW, have another question posted. Sure its a simple answer for you and your huge knowledge base 
As of 10.6, building dates from strings has become even more unreliable, though. For example, your snippet now actually ignores my date format settings and uses the US settings.
It’s a bit more typing to do it the following way, but I reckon it’s worth the effort:
set thisDate to (current date) -- a starting date
set day of thisDate to 1 -- important
set year of thisDate to 2010
set month of thisDate to 1
set day of thisDate to 4