Q57853: BASIC 7.00 WindowDo Doesn’t Trap Click in Current Window
Article: Q57853 Product(s): See article Version(s): 7.00 Operating System(s): MS-DOS Keyword(s): ENDUSER | SR# S891113-16 | mspl13_basic Last Modified: 20-JAN-1990 The WindowDo procedure of the WINDOW.BAS toolbox file that is included with Microsoft BASIC Professional Development System (PDS) Version 7.00 for MS-DOS will not trap a click in the current window unless that click is in a button or edit field. To work around this limitation, open an "area" button (button type 4) in the current window that is exactly the same size as the current window. This does not make the WindowDo procedure trap clicks in the current window (it is only trapping a click in a button), but it appears so because an area button is invisible. 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 up two windows. For simplicity, we will assume that 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" 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: '$INCLUDE: 'general.bi' 'These INCLUDE, COMMON SHARED, and DIM '$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.
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