How to eat keydown message to prevent beep?

Mike Hubbard

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Feb 8, 2005, 2:46:37 PM2/8/05

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I need the OnKeyDown event handler of a form to be executed, but how
do I eat the message to prevent the beep? I can use the OnShortCut
event handler and set handled to true, but I don't know how to test
for Ctrl-F in that event handler since there is no ShiftState
parameter.

Thanks

Mike

Liz

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Feb 8, 2005, 3:11:18 PM2/8/05

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Mike Hubbard wrote:

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);

??

Mine has shift

So,

if (ssctrl in shift) and (chr(key)='F') then showmessage('Ctrl+F
detected');

same with keyup

set the key to 0 to cancel its action.

Mike Hubbard

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Feb 8, 2005, 3:53:34 PM2/8/05

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>procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
> Shift: TShiftState);
>
>??
>
>Mine has shift
>

Yeah, my keydown declaration is the same, and I know how to test the
shiftstate, but how do I prevent the beep? That was the question.

>
>set the key to 0 to cancel its action.

I tried this and the beep still occurs.

Mike

Liz

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Feb 8, 2005, 4:17:29 PM2/8/05

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Mike Hubbard wrote:

> I tried this and the beep still occurs.

Well ctrl+F doesnt cause a beep by default, so, what exactly is causing
the beep? normally the beep is pressing enter..

Iain Macmillan

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Feb 9, 2005, 11:33:54 AM2/9/05

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In article <42092c69$1...@newsgroups.borland.com>, "Liz"
<liz_want...@xcalibur.nospam.co.uk> wrote:

>> I tried this and the beep still occurs.
>
> Well ctrl+F doesnt cause a beep by default, so, what exactly is causing
> the beep?

eating the keydown. <g>

He'll have to eat ctrl-F in keyup too.

if you were told someone had come back in when as far as you knew they
hadn't gone out, wouldn't you beep too? %).

Mike Hubbard

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Feb 9, 2005, 1:00:44 PM2/9/05

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On 8 Feb 2005 13:17:29 -0800, "Liz"
<liz_want...@xcalibur.nospam.co.uk> wrote:

>Well ctrl+F doesnt cause a beep by default, so, what exactly is causing
>the beep? normally the beep is pressing enter..

It looks to me like the Ctrl-F is causing the beep. It is a WM_CHAR
message that gets dispatched and then some assembly code results in
the beep. What else do I need to look at?

Mike

Mike Hubbard

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Feb 9, 2005, 1:01:45 PM2/9/05

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>> Well ctrl+F doesnt cause a beep by default, so, what exactly is causing
>> the beep?
>eating the keydown. <g>
>
>He'll have to eat ctrl-F in keyup too.
>

It beeps even if I don't do anything to eat the keydown.

Mike

Mike Williams (TeamB)

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Feb 9, 2005, 1:29:36 PM2/9/05

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Mike Hubbard wrote:

> In searching more, I found that if I enter any Ctrl + SomeChar in any
> control that has focus such as an edit box in a modal form, I get a
> beep. What is causing this?

That's just standard windows behavior. It's letting the user know that
they pressed a key that didn't actually do anything useful. You'll
notice this if you simply create a new project in Delphi and drop a
tEdit on it. Ctrl+F will cause a beep. Ctrl+A will cause a beep.
Ctrl+C, Ctrl+X, Ctrl+V, etc. will not cause a beep since those
keystrokes are consumed at a lower level for clipboard operations.

--
-Mike (TeamB)

Mike Hubbard

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Feb 9, 2005, 1:20:11 PM2/9/05

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>Well ctrl+F doesnt cause a beep by default, so, what exactly is causing
>the beep? normally the beep is pressing enter..

In searching more, I found that if I enter any Ctrl + SomeChar in any

control that has focus such as an edit box in a modal form, I get a
beep. What is causing this?

Mike

Iain Macmillan

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Feb 9, 2005, 2:20:16 PM2/9/05

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In article <r0lk0190poj5ceigr...@4ax.com>, Mike Hubbard
<mmhu...@socal.rr.com> wrote:

>>Well ctrl+F doesnt cause a beep by default,

Hmm, take that back Liz!
I agree with the next para, at least if somechar is 'F'. (or ABDEGI...)

> In searching more, I found that if I enter any Ctrl + SomeChar in any
> control that has focus such as an edit box in a modal form, I get a
> beep.

So they do.
Most of my edits have a restriction of some kind in OnKeyPress, which says
what chars I will allow (e.g. numbers) so they don't beep as ctrl-F is not a
number.. so clearly eating it here works.

Despite what it says in help on OnKeyPress about handling extended chars in
OnKeyDown I'd expect therefore that an OnKey*Press* handler reading
if key=chr(6) then key:=chr(0);
would suppress Ctrl-F.

> What is causing this?
.. what Mike W. says. %).

Mike Hubbard

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Feb 9, 2005, 2:35:23 PM2/9/05

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On 9 Feb 2005 10:29:36 -0800, "Mike Williams (TeamB)"
<mlwil...@gmail.com> wrote:

>That's just standard windows behavior. It's letting the user know that
>they pressed a key that didn't actually do anything useful. You'll
>notice this if you simply create a new project in Delphi and drop a
>tEdit on it. Ctrl+F will cause a beep. Ctrl+A will cause a beep.
>Ctrl+C, Ctrl+X, Ctrl+V, etc. will not cause a beep since those
>keystrokes are consumed at a lower level for clipboard operations.

That makes sense to me, but when I trap for the Ctrl-F to execute a
buttons event handler, how can I prevent the beep from occurring? The
KeyDown event handler code is as follows:

// control-f is shortcut for find button
if (btnFind.Enabled and (ssCtrl in Shift) and
((Key = Ord('f')) or (Key = Ord('F')))) then
btnFindClick(Sender);

This code works fine, but the beep is confusing to the user.

Thanks for all the help.

Mike

Mike Williams (TeamB)

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Feb 9, 2005, 3:12:17 PM2/9/05

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Mike Hubbard wrote:

> That makes sense to me, but when I trap for the Ctrl-F to execute a
> buttons event handler, how can I prevent the beep from occurring? The
> KeyDown event handler code is as follows:
>
> // control-f is shortcut for find button
> if (btnFind.Enabled and (ssCtrl in Shift) and
> ((Key = Ord('f')) or (Key = Ord('F')))) then
> btnFindClick(Sender);
>
> This code works fine, but the beep is confusing to the user.
>
> Thanks for all the help.

I think you're making it too hard on yourself. How is the user
supposed to know to press Ctrl+F anyhow? The normal way to do this is
to use a menu (either a main menu or popup menu) with a Ctrl+F
shortcut. When you do that the sound goes away anyhow and you don't
have to write code like the above ...

--
-Mike (TeamB)

Mike Hubbard

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Feb 9, 2005, 3:52:13 PM2/9/05

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>I think you're making it too hard on yourself. How is the user
>supposed to know to press Ctrl+F anyhow? The normal way to do this is
>to use a menu (either a main menu or popup menu) with a Ctrl+F
>shortcut. When you do that the sound goes away anyhow and you don't
>have to write code like the above ...

The form is a modal form, and the reason for this is that it what the
user requested. So how can I prevent the beep?

Thanks

Mike

Patrick

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Feb 9, 2005, 4:05:04 PM2/9/05

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> The form is a modal form, and the reason for this is that it what the
> user requested. So how can I prevent the beep?

On XP, you could get out the sledgehammer and stop the beep service (sc stop
beep) and start it again (sc start beep).
Ick.

Patrick

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Feb 9, 2005, 4:15:49 PM2/9/05

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Looks like you can do this programatically via the WinSvc unit. I should
have confirmed this prior to posting my previous statement.

Mike Williams (TeamB)

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Feb 9, 2005, 4:50:20 PM2/9/05

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Mike Hubbard wrote:

> The form is a modal form, and the reason for this is that it what the
> user requested. So how can I prevent the beep?

Like I said, add popup menus with the appropriate shortcuts. It's
*supposed* to beep for any other key.

--
-Mike (TeamB)

Mike Hubbard

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Feb 9, 2005, 5:02:43 PM2/9/05

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>Like I said, add popup menus with the appropriate shortcuts. It's
>*supposed* to beep for any other key.

Thanks! I get it now. I hadn't thought of using a popup menu for
the form with AutoPopup set to False. That is the right way to do it.

Mike