Add Backspace function to PL/SQL button

Question

Hello,
I am implementing a POS interface in oracle forms 6i and I am confused upon how to create the backspace function on a pl/sql button. I have added these to the WHEN-BUTTON-PRESSED trigger:
SELECT substr(:system.current_item, 1, (LENGTH(:system.current_item) - 1))
INTO lv_return
FROM dual ;
The problem is that I did not manage to get a dynamic reference to my current (selected) item on runtime. That is I only get it as a value and not as an item reference, where I can assign the lv_return value from above.
Any suggestions?
thank you.

Answer 1

Hello,
In a more general way you could use the d2kwutil Win_Api_Shell.SendKeys() function to simultate a keybord hit:
Description
Plays back Keystroke Macros to an application. You can combine keystrokes together in a macro and apply modifiers to them. Generally function keys can be addressed to the MDI window. Other sets of Keystrokes e.g. Sending Ctrl+Home to a Multi line text item are best done in the When-new-item-instance trigger of that item, using the Window_Handle for the item obtained by the Form Builder build-in Get_Item_Property.
Syntax
PROCEDURE Win_Api_Shell.SendKeys
(hWnd IN PLS_INTEGER,
Keys IN VARCHAR2,
RaiseExceptions IN BOOLEAN DEFAULT FALSE);
Parameters
Target
     The Window handle of the window you want to send the keystrokes to. You can get this handle by using the GET_WINDOW_PROPERTY built-in.
Keystrokes
     The keystrokes that you want to send to the window. Use these characters for modifier keys:
     Shift = +;
     Control = ^;
     Alt = %.
Modifiers can be ?Escaped? by enclosing them in braces {}.
To apply the modifiers to a sequence of keys, enclose the keys in brackets, as in "^(abc)". Other special keys are enclosed in braces thus:
{Backspace}
{Break}
{CapsLock}
{Clear}
{Delete}
{End}
{Enter}
{Esc}
{Help}
{Home}
{Insert}
{NumLock}
{PgDown}
{PgUp}
{PrtSc}
{ScrollLock}
{Tab}
{F1} - {F12}
{Up}
{Down}
{Left}
{Right}
RaiseExceptions If TRUE, then if the procedure fails to send or parse the keystrokes, the explicit PL/SQL exception NO_DATA_FOUND will be raised
In your case you could use the following:
win_api_shell.sendkeys(get_window_property('WINDOW1',window_handle),'{Backspace}',TRUE);
Francois