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Dialog context help support problem (VC++, MFC)

Posted on 1999-10-07
Medium Priority
Last Modified: 2011-10-03
I have some problem with context help support at dialog boxes. I need 3 kind of help:
1. Whole dialog help (called by pressing F1).
2. Context help for dialog controls in popup windows (called by pressing Help Button in dialog caption, and then hitting some control).
3. Context help for dialog controls in popup windows (called through context menu "What's this?" by right mouse click on the control).
I realised 2 and 3 approachs but i don't know how to catch whole dialog help at F1 key instead calling focused element context help.
Is anybody help me? I will be appreciate any comments.
Question by:turchan
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LVL 15

Expert Comment

by:Tommy Hui
ID: 2107381
Since you didn't specify if you're using any windows framework, I'll assume you're using WinAPI. In your message loop, you probably have something like this:

  while (GetMessage(...))
    if (!IsDialogMessage(...))

The problem is that IsDialogMessage is eating the F1 key. So instead, you should check to see if the F1 key is hit and then do a context search to bring up the appropriate help.

Author Comment

ID: 2115299
I'm using MFC, not WinAPI, and haven't direct access to message loop.
LVL 15

Expert Comment

by:Tommy Hui
ID: 2115585
You should then override PreTranslateMessage(). Take a look at the online help for that function.
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Author Comment

ID: 2115756
I've already overrided PreTranslateMessage().
I'm trying to disable following dispatching of F1 WM_KEYDOWN message, but despite of this the calling of OnHelpInfo is processed after (or at the same time) the processing of F1 WM_KEYDOWN message.

Accepted Solution

despote earned 800 total points
ID: 2121360

If you want to trap the F1 message you can do that
//  source scope
#define HK_F1 1 // Your value
WORD hk = 112;  // F1
// Add this line on the message map
// and define & implement the OnHotKey function
// as usual
CYourClass::OnHotKey( UINT nID, LPARAM lParam )
//  You must be sure than nID is YOUR HotKey
    switch( nID)
         case HK_F1:

// Add this to your code
   RegisterHotKey( m_hWnd, HK_F1, HIBYTE( hk), LOBYTE( hk))
   unregisterHotKey( m_hWnd, HK_F1);

The other side, is that while your dialog is present, the F1 key will be redirected to your application for all the system. but you can try to catch some killfocus or other api...

Author Comment

ID: 2123083
Thank you, despote. It works fine.

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