Announcement

**Michael Mattias** · 12 Sep 2001, 04:05 AM

Don't know what MS have been thinking

Call me a naif, but if CBCTL does not return the same value as GetDlgCtrlID(GetFocus), and lParam is not available under DDT, and using the API call rather than the DDT function produces the correct value, wouldn't that mean the problem is located several hundred miles south of Redmond WA?

I mean, I use SDK-style programming all the time, where LOWRD(wParam) is the control ID, and I've never gotten the wrong control on a button click.

MCM

**Borje Hagsten** · 12 Sep 2001, 05:34 AM

Had to test. Same problem in SDK, so a Redmond-based problem. Even
stranger - it seems it only happens every other time. SDK test:

Code:

'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
' Simple SDK-style template
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
#COMPILE EXE
#INCLUDE "WIN32API.INC"
 
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
' Main entrance
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
FUNCTION WINMAIN (BYVAL hInst AS LONG, BYVAL hPrevInstance AS LONG, _
                  lpCmdLine   AS ASCIIZ PTR, BYVAL iCmdShow AS LONG) AS LONG
 
  LOCAL hWnd AS LONG, hBtn1 AS LONG, hBtn2 AS LONG, style AS LONG
  LOCAL Msg        AS tagMsg
  LOCAL szAppName  AS ASCIIZ * 50
  LOCAL wndclass   AS WndClassEx
  LOCAL rc         AS RECT
 
  szAppName              = "MYPROG"
  wndclass.cbSize        = SIZEOF(WndClass)
  wndclass.style         = %CS_HREDRAW OR %CS_VREDRAW
  wndclass.lpfnWndProc   = CODEPTR( WndProc )
  wndclass.hInstance     = hInst
  wndclass.hCursor       = LoadCursor( %NULL, BYVAL %IDC_ARROW )
  wndclass.hbrBackground = GetStockObject(%LTGRAY_BRUSH)
  wndclass.lpszClassName = VARPTR( szAppName )
 
  IF registerClassEx(wndclass) = 0 THEN EXIT FUNCTION 'what else to do..?
 
  SystemParametersInfo %SPI_GETWORKAREA, BYVAL 0, VARPTR(rc), 0 'for centering on screen
 
  'Create a window using the registered class
  hWnd = CreateWindow(szAppName, _                           ' window class name
                      "Press Right arrow, then Enter - repeat", _ ' window caption
                      %WS_CAPTION OR %WS_SYSMENU, _          ' window style
                      ((rc.nRight - rc.nLeft) - 300) / 2, _  ' initial x position
                      ((rc.nBottom - rc.nTop) - 200) / 2, _  ' initial y position
                      300, _                                 ' initial x size
                      200,_                                  ' initial y size
                      %NULL, _                               ' parent window handle
                      %NULL, _                               ' window menu handle
                      hInst, _                               ' program instance handle
                      BYVAL %NULL)                           ' creation parameters
 
  style = %WS_CHILD + %WS_VISIBLE + %WS_TABSTOP
  hBtn1 = CreateWindow("BUTTON", "&OK", style, 70, 140, 80, 22, hwnd, %IDOK, hInst, %NULL)
  hBtn2 = CreateWindow("BUTTON", "E&xit", style, 150, 140, 80, 22, hwnd, %IDCANCEL, hInst, %NULL)
  SetFocus hBtn1
 
  'Display the window on the screen
  ShowWindow hWnd, iCmdShow : UpdateWindow hWnd
 
  'Main message loop:
   While GetMessage(Msg, %NULL, 0, 0)
      If IsDialogMessage (hWnd, Msg) Then
      Else
         TranslateMessage Msg
         DispatchMessage  Msg
      End If
   Wend
 
  FUNCTION = msg.wParam
END FUNCTION
 
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
' Main dialog procedure
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
FUNCTION WndProc (BYVAL hWnd AS LONG, BYVAL wMsg AS LONG, _
                  BYVAL wParam AS LONG, BYVAL lParam AS LONG) EXPORT AS LONG
 
  SELECT CASE wMsg
     CASE %WM_COMMAND
        IF HIWRD(wParam) = %BN_CLICKED THEN
           SELECT CASE LOWRD(wParam)  'GetDlgCtrlID(GetFocus)  'fixes problem!
              CASE %IDOK     : MSGBOX "IDOK"
              CASE %IDCANCEL : MSGBOX "%IDCANCEL"
           END SELECT
           SetFocus GetDlgItem(hWnd, %IDOK) 'return focus to first control, IDOK
        END IF
 
     CASE %WM_DESTROY
        PostQuitMessage 0
        FUNCTION = 0 : EXIT FUNCTION
 
  END SELECT
  FUNCTION = DefWindowProc(hWnd, wMsg, wParam, lParam)
END FUNCTION

------------------

**Semen Matusovski** · 12 Sep 2001, 06:57 AM

In both cases results depends of IsDialogMessage.
I avoid %IDOK, %IDCANCEL as button's id.s to have a possibility to recognize real "click".

------------------
E-MAIL: [email protected]

**Lance Edmonds** · 12 Sep 2001, 07:08 AM

I concur.

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

**Borje Hagsten** · 12 Sep 2001, 08:43 AM

Just wanted to tell, since it can give dangerous result. Like I said,
imagine question was "Format drive C?", etc. Using other id's, also
strange result, but not as dangerous. Then if dialog gives button focus
(ie, first control in tab order), Right arrow + Enter works/works not,
every other time. No danger if it sometimes doesn't work, but..

Personally, think I'll avoid using MS buttons in "commercial" code from here on..

------------------

**Dominic Mitchell** · 12 Sep 2001, 09:10 AM

Borje;
In standard sdk style GUI programming the tab and arrows keys work as expected.
However, keyboard handling in Microsoft Windows, as noted by some authors,
seems to have been an afterthought. When one tries to change the keyboard focus
programmatically in a window that contain a pushbutton with an id of IDOK
things go awry. There are also related visual problems with the BS_PUSHBUTTON/
BS_DEFPUSHBUTTON styles.
In other words the problem is that call to SetFocus in WM_COMMAND.
SetFocus and IsDialogMessage ain't that great a couple.
To return the focus to the first control do the following-

Code:

  SELECT CASE wMsg
     CASE %WM_COMMAND
        IF HIWRD(wParam) = %BN_CLICKED THEN
           SELECT CASE LOWRD(wParam)
              CASE %IDOK     : MSGBOX "IDOK"
              CASE %IDCANCEL : MSGBOX "%IDCANCEL"
           END SELECT
           PostMessage hWnd, %WM_KEYDOWN, %VK_TAB, 0  
        END IF

The following is off topic but may be useful to lurkers.
Your WM_COMMAND filter as it stands does not handle the default behaviour
of windows with IsDialogMessage() in the message loop. The test

IF HIWRD(wParam) = %BN_CLICKED THEN

prevents the following cases from being trapped
(they all generate IDCANCEL but with HIWRD(wParam) = 0)-
1. User closing the window via the system menu.
2. User closing the window via the x button in the title bar.
3. User closing the window by pressing the Escape key.

I would rewrite the code as follows(no need for WM_SYSCOMMAND)-
1. filter on control ids(usually unique numeric values set by programmer)
2. filter on notifications(numeric values may not be unique and are set by MS)

Code:

  CASE %WM_COMMAND
    SELECT CASE LOWRD(wParam)
      CASE %IDC_APPLY
        IF HIWRD(wParam) = %BN_CLICKED THEN
          MSGBOX "APPLY"
        END IF

      CASE %IDOK
        MSGBOX "IDOK"

      CASE %IDCANCEL
        MSGBOX "%IDCANCEL"
    END SELECT

[This message has been edited by Dominic Mitchell (edited September 12, 2001).]

**Borje Hagsten** · 12 Sep 2001, 10:51 AM

Theory is correct, yes - but %BN_CLICKED = 0, so Esc still works.
Reason for testing BN_CLICKED is so button isn't triggered on wrong
notification.

------------------
Forgot to add: If a button has BS_NOTIFY style, it can cause highly
unpredictable results if not BN_CLICKED is tested. Not sure for regular
button, but think things like CONTROL DISABLE (EnableWindow) triggers
notification. To be on safe side - always test BN_CLICKED.

[This message has been edited by Borje Hagsten (edited September 12, 2001).]

**George Bleck** · 12 Sep 2001, 06:56 PM

(My $.02)

I am an old DOS programmer and feel more comfortable using the keys then the mouse at times.

From experience, I NEVER use the enter key as it would trigger the default button, rather, I use the spacebar to activate the focused key.

------------------
George W. Bleck
Senior System Engineer
KeySpan Corporation

Announcement

Button warning..

Button warning..

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment