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)
dlg
. This is aui.DIALOG
object referencing the current dialog. The dialog can implement anINPUT
,INPUT ARRAY
,DISPLAY ARRAY
,MENU
, orCONSTRUCT
. For more information, see The Dialog class in Genero Business Development Language User Guide.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 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
.
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)
DISPLAY "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
DISPLAY "dlgEvent_recAccount_BeforeDelete (Row scope) is exited"
RETURN dlgCtrlInstruction
END FUNCTION