Basic 7.0/7.1 WindowDo Does Not Trap Click in Current Window (57853)

MORE INFORMATION

The WindowDo procedure allows you to trap window events such as selecting buttons and edit fields, resizing, moving, or closing a window, and selecting a window other than the current window. However, WindowDo cannot trap a click in the current window itself unless the click occurs on a button or edit field in that window.

For example, suppose a program opens two windows. For simplicity, assume there are no buttons or edit fields opened in either window. By default, the last window opened (window2) is the current window. The WindowDo procedure will trap a click in the other window (window1) but not in window2. This is a design limitation of the WindowDo procedure and is not considered a problem.

To easily work around this situation, in the current window, open an area button (button type 4) that is exactly the same size as the current window. The WindowDo procedure is still trapping a click in a button, but it appears as if a click is being trapped anywhere in the window because the button is hidden. Type 4 buttons are invisible.

For a detailed explanation of the WindowDo procedure, see page 572 of the "Microsoft Basic Version 7.0: Language Reference" versions 7.0 and 7.1 manual. For more information on area buttons (button type 4), see the ButtonOpen procedure on page 557 of the same manual.

The following example program illustrates the limitation and its workaround:

Example

'$INCLUDE: 'general.bi'   'These INCLUDE, COMMON SHARED, and DIM
'$INCLUDE: 'mouse.bi'     'statements are generally those needed
'$INCLUDE: 'menu.bi'      'for using the User Interface Toolbox.
'$INCLUDE: 'window.bi'

COMMON SHARED /uitools/ GloMenu           AS MenuMiscType
COMMON SHARED /uitools/ GloTitle()        AS MenuTitleType
COMMON SHARED /uitools/ GloItem()         AS MenuItemType
COMMON SHARED /uitools/ GloWindow()       AS WindowType
COMMON SHARED /uitools/ GloButton()       AS ButtonType
COMMON SHARED /uitools/ GloEdit()         AS EditFieldType
COMMON SHARED /uitools/ GloStorage        AS WindowStorageType
COMMON SHARED /uitools/ GloWindowStack()  AS INTEGER
COMMON SHARED /uitools/ GloBuffer$()

DIM GloTitle(MAXMENU)           AS MenuTitleType
DIM GloItem(MAXMENU, MAXITEM)   AS MenuItemType
DIM GloWindow(MAXWINDOW)        AS WindowType
DIM GloButton(MAXBUTTON)        AS ButtonType
DIM GloEdit(MAXEDITFIELD)       AS EditFieldType
DIM GloWindowStack(MAXWINDOW)   AS INTEGER
DIM GloBuffer$(MAXWINDOW + 1, 2)

CLS
CALL WindowInit   'Initialize window and mouse routines.
CALL MouseInit

'Open window1. It is the current window..
CALL WindowOpen(1, 4, 20, 20, 36, 14, 1, 14, 1, 15, FALSE, FALSE,_
                FALSE, FALSE, 1, "Window 1")

'Open window2, it is now the current window.
CALL WindowOpen(2, 4, 45, 20, 61, 14, 1, 14, 1, 15, FALSE, FALSE,_
                FALSE, FALSE, 1, "Window 2")

CALL MouseShow        'Show the mouse cursor.

CALL WindowDo(0, 0)   'Wait for a window event to happen.
                      'The program will not continue until window1 is
                      'clicked. This is because clicking in window2
                      '(the current window) is not trapped by the
                      'WindowDo procedure.

'Assume window1 is the current window now.

'Open an area button in the current window that is the same size as
'the current window.
CALL ButtonOpen(1, 0, "", 1, 1, 17, 17, 4)

CALL WindowDo(0, 0)   'Wait for a window event to happen.
                      'The program will continue if either window is
                      'clicked. Clicking window2 will be trapped
                      'because it is not the current window. Clicking
                      'window1 will be trapped because there is a
                      'button (although invisible) in window1 that
                      'is the same size as window1.