TPageControl Tabs on Bottom in MSWindows
lazarus / 31-LCL

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Avishai · 2013-05-05 05:07

On MSWindows TPageControl draws the Tabs differently depending on
TabPosition if Themes are active.  Only tpTop, tpLeft and tpRight are
useable.  tpBottom looks disconnected. tpLeft and tpRight draws them
WindowsClassic and tpTop draws them according to Themes.

But I found code that will turn Themes off only for TPageControl
making them consistent for all positions as WindowsClassic.  Some may
not like the look, but if you need the tabs on the bottom or just
prefer the Classic look, this seems to work very well.  I only found
it a few minutes ago so it's NOT well tested.

Code: [Select]uses UxTheme;

UxTheme.SetWindowTheme(PageControl1.Handle, NIL, '');

It 'might' be a good idea to introduce a new property for TPageControl
to turn Themes off only for that control (MSWindows only). Personally,
I prefer the Classic look anyway.

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exdatis · 2013-05-05 07:12

Very useful, thank you!
Regards

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Avishai · 2013-05-06 18:15

If you use MSWindows, this might be useful for those that prefer the
Windows Classic look for TPageControl, or if you need the Tabs at the
bottom.

Code: [Select]uses UxTheme;

procedure FixPageControl(ACtrl: TObject);  // Turns Themes off for
TPageControl
begin
  {$IfDef Windows}
  if ACtrl is TPageControl then begin
    UxTheme.SetWindowTheme(TPageControl(ACtrl).Handle, NIL, '');
  end;
  {$EndIf}
end;

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Avishai · 2013-05-09 12:11

This is a screenshot of TPageControl showing Themes ON and Themes OFF.

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Avishai · 2013-05-13 10:32

I think I have figured out a way to fix TPageControl for MSWindows but
I don’t have the skills to write it.  The first problem is that when
it first shows, the color of the Active TabSheet is white until you
change the active Tab at run-time and then go back to the previous
Tab.  The second problem is that when it is Themed, it looks horrible.

I did some experiments and found that I could create a TCustomControl
at run-time to cover the TabSheet.  That solved the Color issue.  The
TCustomControl Cover could be added to the TTabSheet Create with 
ControlStyle:= ControlStyle - [csNoDesignSelectable].

The horrible appearance is much easier.  This code turns off Themes
for the TPageControl:

Code: [Select]uses UxTheme;

UxTheme.SetWindowTheme(PageControl1.Handle, NIL, '');

I think Property Color should be published for TTabSheet and a
Property Themed could be added to TPageControl.

If anyone wants to give this a try, I would appreciate it and I expect
a lot of others would as well.