TTabControl switching with <CTRL>-<TAB>

[masonwheeler]

I put a TTabControl on my form, and to my great surprise, I'm not able to switch between tabs with <CTRL>-<TAB> at runtime. I thought this was default behavior; every app I've ever used with a tabbed control will do this. How do I implement the behavior, so that if I press <CTRL>-<TAB> (or <CTRL>-<SHIFT>-<TAB>) in a form with a TTabControl on it, no matter which component currently has the focus, the TTabControl will move to the next (previous) tab and call it's onChange event?

Mason

 

[DelphiAaron]

strange request, but it can be done.

this will move focus between controls, as soon as the tab gets focus it will change tabs.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ComCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    TabControl1: TTabControl;
    procedure FormKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
  private
    { Private declarations }
    Procedure CMDialogKey(Var Msg: TWMKey); message CM_DIALOGKEY;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  CurrentTab: Integer;

implementation

{$R *.DFM}
procedure TForm1.CMDialogKey(var Msg: TWMKey);
begin
 if (TabControl1.Focused) then
    Msg.Result := 0
 else
 inherited;
end;

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
if (ssShift in Shift) and (Ord(Key) = VK_TAB) then
 begin
  if CurrentTab>0 then
   if Ord(Key) = VK_TAB then TabControl1.TabIndex:=CurrentTab-1;
   CurrentTab:=TabControl1.TabIndex;
   exit;
 end;

if Ord(Key) = VK_TAB then
 if CurrentTab<TabControl1.Tabs.Count then
  TabControl1.TabIndex:=CurrentTab+1;
 CurrentTab:=TabControl1.TabIndex;
end;

end.
[\code]

Aaron

 

[DelphiAaron]

woops, i just saw that you want ctrl tab.
anyways you should be able to modify what ive posted.

Aaron

 

[DelphiAaron]

oh yeh , you need to enable form keypreview.

Aaron

 

[masonwheeler]

Interesting. I'm reading over the code, and I understand most of it, but what does the CMDialogKey procedure do? Messages are mostly a mystery to me, and I don't see what this one's doing.

Also, how do you "enable form keypreview"? (And if that's what I think it is, it might solve another problem I've been having, so knowing how to do it would be quite helpful to me.)

Mason

 

[Opieo]

When you have the form selected in the Design, under the Input section is the KeyPreview property.
=)

~
Give a man some fire, he will be warm for a day, Set a man on fire, he will be warm for the rest of his life.

 

[masonwheeler]

I managed to get it working. Aaron's code didn't work completely (maybe he's using a different version of Delphi?) but it gave me a place to start from. Also, the Message thing did nothing whatsoever (as far as I can tell) and I ended up removing it.

Here's what I ended up with, in case anyone wants to see a working solution for BDS '06.

procedure TfrmMyForm.FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if (ssCtrl in Shift) and (Ord(Key) = VK_TAB) then
begin
if ssShift in Shift then
if TabControl.tabIndex > 0 then
TabControl.TabIndex := TabControl.tabIndex - 1
else
TabControl.TabIndex := TabControl.tabs.Count - 1
//end if
else
if TabControl.tabIndex < TabControl.Tabs.Count - 1 then
TabControl.TabIndex := TabControl.tabIndex + 1
else
TabControl.TabIndex := 0;
//end if
//end if
FocusControl(TabControl);
TabControl.OnChange(self);
end;
end;

Thanks for the help!

Mason