Re: Don't want a default button

From: Dragon Lord (invalid_at_joke.com)
Date: 02/02/04 

Date: Mon, 2 Feb 2004 13:38:31 -0500

Here is some sample code

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Buttons, ExtCtrls;

type
  TBitBtnHack = class(TBitBtn)
    public
      procedure WndProc(var Message: TMessage); override;
  end;

  TForm1 = class(TForm)
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    private
    public
      procedure OnClicky(Sender: TObject);
      procedure WndProc(var Message: TMessage); override;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TBitBtnHack.WndProc(var Message: TMessage);
begin
  writeln('BUTTON MESSAGE: ', IntToHex(Message.Msg,8));
  inherited WndProc(Message);
end;

procedure TForm1.WndProc(var Message: TMessage);
begin
  writeln('FORM MESSAGE: ', IntToHex(Message.Msg,8));
  inherited WndProc(Message);
end;

procedure TForm1.OnClicky(Sender: TObject);
begin
  writeln('on click fired');
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  MyButton: TBitBtnHack;
begin
  MyButton := TBitBtnHack.Create(Form1);
  Form1.InsertControl(MyButton);
  MyButton.OnClick := OnClicky;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  writeln('-----------------------------------------------');
end;

end.

Produces this in the console window when a key is pressed

BUTTON MESSAGE: 0000BD00 CN_KEYDOWN
BUTTON MESSAGE: 0000B02E CM_CHILDKEY
FORM MESSAGE: 0000B02E CM_CHILDKEY
BUTTON MESSAGE: 0000B01E CM_WANTSPECIALKEY
BUTTON MESSAGE: 00000087 WM_GETDLGCODE
FORM MESSAGE: 0000B005 CM_DIALOGKEY
BUTTON MESSAGE: 0000B005 CM_DIALOGKEY
on click fired
BUTTON MESSAGE: 00000084 WM_NCHITTEST

changing the code slightly

procedure TForm1.WndProc(var Message: TMessage);
begin
  writeln('FORM MESSAGE: ', IntToHex(Message.Msg,8));
  if Message.Msg = CM_CHILDKEY then
    Message.Result := 1;
  inherited WndProc(Message);
end;

BUTTON MESSAGE: 0000BD00
BUTTON MESSAGE: 0000B02E
FORM MESSAGE: 0000B02E
BUTTON MESSAGE: 00000084

to just trap the CM_CHILDKEY you can put a handler for JUST that event, this
is just for testing purposes. But, as you can see, if you handle that even
(Message.Result:=1) then the Button ingores it. You COULD also trap the
CM_DIALOGKEY.

Jeremy

"J French" <erewhon@nowhere.com> wrote in message
news:401e8a6e.9588444@news.btclick.com...
> On Mon, 2 Feb 2004 12:21:15 -0500, "Dragon Lord" <invalid@joke.com>
> wrote:
>
> >Actually, Windows doesn't steal it, but actually, the VCL steals it in
the
> >form of a custom message. CM_CHILDKEY.
>
> Are you really sure about that ?
>
>