New component question!

Hi!

    I have to build a new combobox component. The list items must be windows
informations....

Example:
  If I set the new property Information to "Windows Date Format" then the
drop down list items must be all of the windows available date format.....
If I set the new property Information to "Windows Currency Format" then the
drop down list items must be all of the windows available currencies
format.....

My principal question is:
    How I can retrieve information from Windows..

My second is :
    How I can rebuild my drop down list when the user will change the
Information property.

Is this an event for that?

I guest it's from Windows Api.

Sorry, I've a bad english....