Key strokes....again!

[Todd Wasson]

Hello,
I'm working on a vehicle model with a 3-D view. It's too hard to drive using mouse clicks on buttons. I've searched through the forums for info on processing key strokes and am lost. Using "Programming Windows 95" as a reference, I still am having problems.
I'm using DDT, and tried getting a key press by capturing %WM_CHAR in the main dialog callback function. The WParam is supposed to be the ASCII code for the key (right?).

CALLBACK FUNCTION Maincallback()
SELECT CASE CBMSG
    CASE %WM_CHAR
         IF CBWPARAM= ASC("A") THEN
            INCR SOMETHING
            END IF

     CASE %WM_TIMER
     CALL DRAW_STUFF()
    END SELECT
END FUNCTION

This attempt is just the latest of many. This main dialog is Modal. Since the program beeps anytime a key is pressed at all, regardless of whether I try to capture anything or not, I haven't continued beyond this. There's numerous postings on this type of thing throughout the forum, and I'd be happy to look at any of them. What should I be looking for? Do I need to (trembling in fear) sub class something? I'd like to use the keypad here, but getting any keys at all to work would be fine.
Thanks!





[This message has been edited by Todd Wasson (edited May 16, 2000).]

[Lance Edmonds]

keystroke messages are translated by the message loop of the window with focus, and dispatched to the appropriate control callback function. the 'problem' is that the message pump for a modal dialog is handled by windows, and therefore you can't intercept the keystoke messages.

there are a few ways to achieve your goal:

1. change the code to use a modeless dialog, and use a getmessage() message pump instead of a dialog doevents pump (you have to provide your own message pump loop for non-modal dialogs and windows). within this loop you can intercept keystroke messages and handle them separately. this is not an "officially supported" technique, but no problems have been reported yet. semen posted some code to do this a couple of months back - http://www.powerbasic.com/support/pb...ead.php?t=2037


2. use a hook function and intercept keystroke messages. see the win32.hlp file topic "hooks".

3. redesign your app to use a native window instead of a dialog (this is an extreme solution!), but this way you can provide a conventional message pump in your winmain() function in which you can trap and handle keystroke messages.

4. subclass all controls on the dialog and handle %wm_char messages. this works until no controls have keyboard focus... not an ideal solution, but this technique does have it's uses:


------------------
lance
powerbasic support
mailto:[email protected][email protected]</a>

[Todd Wasson]

Thanks, Lance. Semen's code works great (as usual ) In PBMAIN(), I used this:

 DIALOG SHOW MODELESS hdlgmain CALL Maincallback
 WHILE GetMessage(Msg, %NULL, 0, 0)
       SELECT CASE Msg.message
              CASE %WM_KEYDOWN
                   SELECT CASE Msg.wParam
                          CASE %VK_LEFT
                               STEERING_ANGLE(4)=STEERING_ANGLE(4)-.25
                               STEERING_ANGLE(1)=STEERING_ANGLE(1)-.25
                          CASE %VK_RIGHT
                               STEERING_ANGLE(4)=STEERING_ANGLE(4)+.25
                               STEERING_ANGLE(1)=STEERING_ANGLE(1)+.25
                          CASE %VK_UP
                               THROTTLE=THROTTLE+100
                          CASE %VK_DOWN
                               THROTTLE=THROTTLE-100
                               
                    END SELECT
       END SELECT
    TranslateMessage Msg
    DispatchMessage Msg
 WEND

Thanks,
Todd Wasson


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

[Semen Matusovski]

Local keyboard hook is enough simple and is very powerful, because allows to refuse from event.

   #Register None
   #Dim All
   #Include "win32Api.inc"
   Global ghKbrdHook As Long
   Global lpfnKbrdHook As Long
   Global hDlg As Long
   
   Function KeyboardHook(ByVal iCode As Integer, ByVal wParam As Long, _
      ByVal lParam As Long) As Dword
      Function = CallNextHookEx(ghKbrdHook, iCode, wParam, lParam)
      If iCode = %HC_ACTION Then
         If IsFalse(lParam And &H80000000) Then ' KeyUp
            Static nHook As Long
            Incr nHook: SetWindowText hDlg, "hook #" + Str$(nHook) + ": " + Str$(wParam)
            'Function = 1: Exit Function ' sample of ignoring !!!
         End If
      End If
   End Function
   
   CallBack Function Cb
      Select Case CbMsg
         Case %WM_INITDIALOG
            ghKbrdHook = SetWindowsHookEx(%WH_KEYBOARD, CodePtr(KeyboardHook), _
               0, GetCurrentThreadId)
         Case %WM_DESTROY: UnhookWindowsHookEx ghKbrdHook
      End Select
   End Function

      Function PbMain
         Local i As Long
         Dialog New 0,"Test",,, 200, 150, %ws_sysmenu To hdlg
         Control Add TextBox, hdlg, 101, "", 10, 10, 180, 12, %WS_BORDER
         Control Add ListBox, hdlg, 102, , 10, 40, 180, 60, %WS_BORDER
         For i = 1 To 5: ListBox Add hDlg, 102, "Item" + Str$(i): Next
         Dialog Show Modal hdlg Call Cb
      End Function

WH_CALLWNDPROC is also very useful hook for such purposes.

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

[Todd Wasson]

Off the subject, how can I copy and paste these code bits quickly and in one big chunk?

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

[Semen Matusovski]

todd --
if you use ie, look http://www.powerbasic.com/support/pb...ad.php?t=22962
i included this program in startup.
select a code in browser, press ctrl-c, then alt-f10.

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

[Lance Edmonds]

Click on the "Edit this Message" icon (the paper and pen icon) above the message. When the edit box appears, simply click, drag and EDIT|COPY. This should work fine with IE. Netscape allows you do it directly from the message thread.


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

[Todd Wasson]

Great, that works fine. Thanks. With the new message pump in there, I'm confused as to how I can display a dialog from a DDT menu without exiting the message pump, or perhaps re-entering the pump when a dialog closes. As it is now, when I pop up my little dialog and close it, the magic keystrokes disappear. How can I get back to Semen's message pump?

Thank you,
Todd


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[Lance Edmonds]

When the menu item is clicked the dialog callback will get a %WM_COMMAND message. In response to this message (picking out the correct control ID obvously), you simply create and display a new dialog... the original code just continues along as it was. If this dialog item launches a modeless dialog, simply start a new DIALOG DOEVENTS message loop immediately after the DIALOG SHOW MODELESS.

Simply substitute your API based message pump for the DIALOG DOEVENTS loop. There is no "problem" having more than one message pump in your code running at the same.

BTW (for the lurkers), there is an example of implementing a standard DDT modeless dialog in the ADDRESS.BAS example.

'Psuedocode
CALLBACK MyCallBack
  SELECT CASE CBMSG
    CASE %WM_COMMAND
      IF CBCTL = ...
         DIALOG NEW...
         CONTROL ADD...
         DIALOG SHOW MODELESS...
         DO 
           DIALOG DOEVENTS
           DIALOG GET SIZE...
         LOOP UNTIL dialogsize = 0
      END IF

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