Description: Appends a message to the validation-error list of the current record.
Calling convention: AddValidationMessage("ValidationMessage": String): Boolean
Parameters:
ValidationMessage: text to append. NULL is ignored.
Returns: True when the message is appended; False when no current DBForm exists or the message is NULL.
Availability: Default; requires a current DBForm.
Example:
AddValidationMessage("Production amount is required.");