dlgEvent_record_BeforeDelete

Function called by dialog code event before user deletes a row.

Syntax

PUBLIC FUNCTION dlgEvent_record_BeforeDelete( 
   dlg ui.DIALOG, 
   uiMode SMALLINT,
   dlgCtrlInstruction libdbappEvents.DlgCtrlInstruction_Type)
  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

The function returns a dialog control instruction value defined by libdbappEvents.DlgCtrlInstruction_Type.

Usage

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

This function is called to overwrite a predefined action to delete a row when a user tries to delete a row in a dialog controlling an INPUT ARRAY. For instance, you can code to cancel the delete operation if the user is not allowed delete rows in the database, or if a database error occurs. The operation is canceled with the instruction to CONTINUE_DIALOG returned in dlgCtrlInstruction.

Note:

Predefined actions are enabled and disabled automatically by the dialog depending on the context. For example, when a static array used by the INPUT ARRAY is full, the insert and append actions get disabled. Even when overwritten, the program will continue to enable and disable the actions automatically.

Example: Before Delete

This example uses the Before Delete Row code event for the Account form in the OfficeStore demo.

In this example if this user is not allowed to delete rows, an error is raised and the insert is canceled in the dlgCtrlInstruction instruction returned. This example uses a user-defined function to verify user capabilities.

PUBLIC FUNCTION dlgEvent_recAccount_BeforeDelete(dlg ui.DIALOG, uiMode SMALLINT,
      dlgCtrlInstruction libdbappEvents.DlgCtrlInstruction_Type)
    RETURNS (libdbappEvents.DlgCtrlInstruction_Type)
  
    CALL libdbappCore.log(C_LOG_INFO, "dlgEvent_recAccount_BeforeDelete (Row scope) is raised")
    IF NOT user_can_delete() THEN
       ERROR "You are not allowed to delete rows"
       LET dlgCtrlInstruction = libdbappEvents.CONTINUE_DIALOG
    END IF      
    CALL libdbappCore.log(C_LOG_INFO, "dlgEvent_recAccount_BeforeDelete (Row scope) is exited")    

    RETURN dlgCtrlInstruction
END FUNCTION

For more information on the libdbappCore.log() function, go to DBAPPDEBUG and the debug level API.