Validating User Input with Xbasic
Frequently you will wish to force a user's input to a form field to be non-blank, within a range, or one of several values. You can achieve these effects with Field Rules, but you can also code them with Xbasic.
The following code attached to the CanDepartevent of the Emailtext field reminds the user to enter a non-blank value.
if (alltrim(Email.text) = "") then ui_beep() cancel() end if
This code attached to the CanDepartevent of the quantityfield checks that the value is within the range 1 to 100.
if alltrim( quantity.text ? < 1) .or. alltrim( quantity.text ?> 100) then ui_msg_box("Invalid Value", "The value entered must be between 1 and 100") cancel() end if
This code attached to the CanDepartevent of the namefield checks that the value is contained within a pre-determined list. This technique might be used as a low-level security mechanism. Most users would find a list boxmore friendly.
dim list as C list= <