HELP: Grabbing CTRL-TAB keystroke in a dialog box

Jeff Thompson -- thompson@in.net
Thursday, June 20, 1996

Environment: MSVC 1.5, WINNT 4.0 BETA2

I was wondering if anybody knows how to do this: I need to intercept
the CTRL-TAB keystroke in a dialog box... I'm trying to implement a
dynamic dialog and switch between sub-dialogs with the CTRL-TAB key. I
can't use the MFC Tab Dialogs (since MSVC 1.5 doesn't have them).

I've tried adding OnChar, OnCommand, OnSysChar, OnSysCommand handlers
but none of them ever get called... What am I doing wrong or what do
I need to do?

Thanks!

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MICHAEL@datatree.com
Saturday, June 22, 1996

[Mini-digest: 3 responses]

Subclass your dialog controls.

Here is how I subclassed a single line
edit control using VC++ 4.1. I believe
VC++ 1.52 is compatible.

MYDIALOG.H
---------------------
CMyEdit m_cpyEdt;

MYDIALOG.CPP
-------------------------
BOOL CMyDialog::OnInitDialog() 
{
    m_cpyEdt.SubclassDlgItem(IDC_COPIES, this);

    // Update from member variables to controls
    CDialog::OnInitDialog();

    return TRUE;
}


// CCPYEdt Subclass for trapping tab and enter keys 

CCPYEdt::CCPYEdt()
{
}

BEGIN_MESSAGE_MAP(CCPYEdt, CEdit)
    //{{AFX_MSG_MAP(CCPYEdt)
    ON_WM_GETDLGCODE()
    ON_WM_KEYDOWN()
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

// CCPYEdt message handlers

UINT CCPYEdt::OnGetDlgCode() 
{
    return DLGC_WANTALLKEYS | DLGC_HASSETSEL;
}

void CCPYEdt::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
    if (nChar == VK_TAB && GetKeyState(VK_SHIFT) & KF_UP)
    {
        // Process Shift+Tab keys
        MessageBeep(0);            //  Do nothing  - sample  code
    }
    else if (nChar == VK_RETURN)
    {       
        // Process Enter key
        MessageBeep(0);            //  Do nothing  - sample  code
    }
    else if (nChar == VK_TAB)
    {
        // Process Tab key
        MessageBeep(0);            //  Do nothing  - sample  code
    }        
    
    CEdit::OnKeyDown(nChar, nRepCnt, nFlags);
}

 
Michael L. Thal
Data Tree Corporation
voice: (619) 231-3300
fax:   (619) 231-3301


-----From: jimt1@voicenet.com (Jim Tannenbaum)

A quick and dirty solution is to use a VBX control (Borland's Visual
Solution Pack or WinWidgets from Lifeboat) that provide Tab Dialog Box
controls.  I've used WinWidgets with mixed results.  I was able to design
with their control, but I had work arround selecting a tab that was not the
left-most tab when I first initialized the dialog box.  Borland supplies
third party VBX controls that work with either Borland 4.5 or MS VC 1.52.

        Good Luck,

          Jet


JJM Systems, Inc                 Phone: (215) 672-3660
1 Ivybrook Blvd, Suite 190       Fax:   (215) 672-5702
Ivyland, PA  19874               Net:   jimt1@voicenet.com


-----From: funduc@sprynet.com

If you were to use 4.0, you could just override PreTranslateMessage().  The 
problem is, in 1.5 we don't have access to the Dialog's proc.  That's why 
PreTranslateMessage is not called and neither are the handlers you mention!  The 
best way, would be to write it with MFC 4.1 but that's not an option is it?

I guess in 1.5, you could subclass your controls, resopond to OnGetDlgCode with 
the base class return or-ed with DLGC_WANTTABS.  Yuk!  You can then send a 
custom WM_COMMAND with WM_USER+something to your parent(the dialog) when you see 
that key and handle it there.  You may then have to make sure you don't break 
standard dialog box TAB key handling (if the control key is not pressed).  In 
other words, set the focus from one control to the next yourself (don't forget 
Shift+TAB)!  Perhaps another good idea would be to pick another key combination!

I've done something similar to catch the VK_RETURN key once (I had to return 
DLGC_DEFPUSHBUTTON for edit fields) and believe me I'm not proud of it.  This 
really makes your code hard to maintain since you have to subclass every control 
in the dialog (use the class Wizard and then modify the class names in the 
header) but it will do the job.  If you find a better way, let me know.  Hope 
this helps.

Mike Funduc
Funduc Software Inc.
funduc@sprynet.com
102372.2530@compuserve.com
http://home.sprynet.com/sprynet/funduc
http://ourworld.compuserve.com/homepages/funduc

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