By setting the pop up calendar on a third field, a trigger performed script can copy the date picked into the correct global date field or even build a date range expression in a text field.
Thanks Phil. I'm guessing the third field must be a global text field?
My current script using 2-calendars is as follows:
Enter Find Mode
Set Field [Event::EvenDate;((Event::_gStartDate &"..."& Event::_gEndDate)
This is triggered upon OnObjectModify on the EndDate field drop down calendar. How would the script have to change to allow both picks from the same calendar and where would the trigger be placed?
Yes a global field, but no not a text field. Make it a field of type date.
The onObjectSave trigger may be a better option for this field. If your layout permits the user to type in the date instead of selecting a date from the pop up calendar, OnObjectModify will be tripped with each keystroke--not what you want here.
I'd define two text fields: gSelectADate, gDateRange.
gDateRange would be a text field.
Your script might look like this.
If [IsEmpty ( Event::gDateRange ) // this is date 1 ]
Set Field [ Event::gDateRange ; Event::gSelectADate ]
SEt Field [Event::gDateRange ; Event::gdateRange & "..." & Event::gSelectADate ]
At this point the script can either stop and you use a button to perform a find script or you include the find script after the End IF:
Enter Find Mode 
Set Field [event::EventDate ; Event::gDateRange ]
Set Error capture [on]
Perform Find