dlgEvent_record_OnChange

Function called after user input has changed a value in a record field.

Syntax

PUBLIC FUNCTION dlgEvent_record_OnChange( 
   dlg ui.DIALOG, 
   uiMode SMALLINT,
   dlgCtrlInstruction libdbappEvents.DlgCtrlInstruction_Type,
   currentField STRING )
  RETURNS (libdbappEvents.DlgCtrlInstruction_Type)

The function parameters are:

  1. dlg. This is a ui.DIALOG object referencing the current dialog. The dialog can implement an INPUT, INPUT ARRAY, DISPLAY ARRAY, MENU, or CONSTRUCT. For more information, see The Dialog class in Genero Business Development Language User Guide.
  2. uiMode. This is an integer value defining the current mode or state in relation to user action in the dialog, form, or application. Modes are defined as constants in the libdbappFormUI file in the libdbapp library.
    Table 1. UI modes
    Description Applies to ... Constant Value
    Display DISPLAY ARRAY C_MODE_DISPLAY 1
    Modify INPUT \ INPUT ARRAY C_MODE_MODIFY 2
    Add INPUT \ INPUT ARRAY C_MODE_ADD 3
    Search CONSTRUCT C_MODE_SEARCH 4
    Empty MENU C_MODE_EMPTY 5
    Exit form The form C_MODE_EXIT_FORM 6
    Exit app The app C_MODE_EXIT_APP 7
    Undefined All (array, form, or app) C_MODE_UNDEFINED 0
  3. dlgCtrlInstruction is a libdbappEvents.DlgCtrlInstruction_Type defining the DIALOG control instruction. Instructions available in the function are shown in the table.
    Table 2. Dialog control instructions
    Description Constant Value
    Accept dialog ACCEPT_DIALOG 1
    Continue dialog CONTINUE_DIALOG 2
    Exit dialog EXIT_DIALOG 3
    Exit menu EXIT_MENU 4
  4. currentField is a string containing the name of the form field that has the focus.

Returns a dialog instruction value defined by the libdbappEvents.DlgCtrlInstruction_Type type.

Usage

When you select the On Change property for the creation of the event, a function shell is created. Enter your code in the function.

This function is called to detect when a field has been changed by user input in INPUT, INPUT ARRAY, or CONSTRUCT dialog after the user moves to a new field. For example, use this function to verify that the field was not left blank. If so, the focus can be returned to the same field so the user may enter a value.

Note: This function can be called only on record fields where the field has a descending or ascending lookup.

Example: On Change

This example uses the On Change code event for a record field in the Account form of the OfficeStore demo.

The function checks the "category.catname" field that has a descending lookup. If the value is NULL, an error message is raised and the focus is returned to the field. 

PUBLIC FUNCTION dlgEvent_record1_OnChange(dlg ui.DIALOG, uiMode SMALLINT, 
                dlgCtrlInstruction libdbappEvents.DlgCtrlInstruction_Type, 
                currentField STRING)
    RETURNS (libdbappEvents.DlgCtrlInstruction_Type)

    DISPLAY "dlgEvent_record1_OnChange (Field scope) is raised"

    DISPLAY "current field: ", currentfield
    CASE currentField
      WHEN "category.catname"
         IF dlg.getfieldValue(currentField) IS NULL THEN
           ERROR " Category is needed "
           LET dlgCtrlInstruction = libdbappEvents.CONTINUE_DIALOG
         END IF 
      OTHERWISE
        -- ...
    END CASE

    DISPLAY "dlgEvent_record1_OnChange (Field scope) is exited"

    RETURN dlgCtrlInstruction
END FUNCTION