[DUG] Stringgrid - intercepting keys

[Jolyon Smith]

First thing I notice is that this key-handling code is occurring on the FORM
not a specific control's key-handling event.  Iirc this makes the code
vunerable to the form's "KeyPreview" setting.

But I'm also somewhat suspicious of CMDialogKey - this looks it might be
specific support for handling typical dialog navigation.  ie return = OK,
escape = Cancel, tab = control navigation.

For other keys wouldn't you simply intercept those keyboard events using the
"normal" windows keyboard event messages, OnKeyDown/Press etc, and handle
those events on the specific tronol, rather than trying to intercept them on
the form before they reach those controls.

That may not be the answer you were looking for but it might set you on the
right track (or elicit some further information about your specific
implementation - such as why you can't handle key events on the control
itself).

Regards,

Jolyon


-----Original Message-----
From: delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz] On
Behalf Of John Bird
Sent: Monday, 5 October 2009 17:26
To: NZ Borland Developers Group - Delphi List
Subject: [DUG] Stringgrid - intercepting keys

For a long time I have been intercepting keys such as Escape/Enter/Tab no 
problem

I have been wanting to put a simple search facility in a string grid, and 
would like to intercept Ctrl/F and F3.....but the code as I am using does 
not get them (D2007) - they are just ignored.

Looks like the only characters I can intercept are Tab, Enter and Escape...

Any suggestions?


procedure TfrmTimeSh2.CMDialogKey(var Msg: TWMKEY);
{
   This converts ENTER key messages to TAB key messages, provided a few
   conditions hold
}
begin
   if   (ActiveControl is TCustomEdit)
    or (ActiveControl is TStringGrid)
   then
     begin
       ATPKeyDir:='';
       if Msg.CharCode = VK_RETURN then
       begin
         Msg.CharCode := VK_TAB;
         ATPKeyDir:='Next';
       end;
       if Msg.Charcode = VK_ESCAPE then
       begin
         Msg.CharCode := VK_TAB;
         ATPKeyDir:='Prev';
       end;
       if Msg.Charcode = VK_F2 then                            <===  never 
intercepted
       begin
         xcGridFind((ActiveControl as TStringGrid),FindStr,strFound);
       end;
       if Msg.Charcode = VK_F3 then              <===  never intercepted
       begin
         xcGridFindNext((ActiveControl as TStringGrid),FindStr,strFound);
       end;
     end;
   inherited;
end;


John 


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