Tech Tip: Cell level entry control for list box

PRODUCT: 4D | VERSION: 13.0 | PLATFORM: Mac & Win

Published On: May 25, 2012

Starting in 4D v13, a cell enterability can be controlled based on specific condition. This ability makes user interface programming flexibility and data driven. Here is an example of how to reject an enterability to a cell when the cell value is empty.

// Object Method: List Box
Case of
  : (Form event=On Before Data Entry)
   C_LONGINT($0;$col_l;$row_l)
   C_POINTER($col_p)
   LISTBOX GET CELL POSITION(*;"List Box";$col_l;$row_l)
   $col_p:=OBJECT Get pointer(Object current)
   If ($col_p->{$row_l}="")
      $0:=0 // Enterable
   Else
      $0:=-1 // Not Enterable
   End if
End case