How can you change the font color of a theme-enabled control?

Question

Yes, this is again this question:

How can I change the font color of a TCheckBox (or any handled control) with Delphi7->Delphi2007 on a themes enabled application?

After reading a lot on the internet and on this site, I found 4 kinds of answer:

1. and Most populare (even from QC): You can't, it's designed like that by Microsoft.
2. Create a component that let you draw it like you want.
3. Buy expensive component set that draws like you want.
4. Do not use themes.

OK, but I am still unhappy with that.

Giving a user colored feedback for the status of a property/data he has on a form, seems legitimate to me.

Then I just installed the MSVC# 2008 Express edition, and what a surprise, they can change the color of the font (property ForeColor of the check box) Then what?

It does not seem to be a "it's designed like that, by Microsoft." then now the question again:

How can I change the font color of a TCheckBox (or any handled control) with Delphi 7 through Delphi 2007 on a theme-enabled application?

Answer 1

This needs some tweak to be perfect solution but worked for me:

Add 2 method to your checkbox component

    FOriginalCaption: string;
    _MySetCap: Boolean;
    procedure WMPaint(var msg: TWMPaint); message WM_PAINT;
    procedure CMTextChanged(var Message: TMessage); message CM_TEXTCHANGED;

and implement this way:

procedure TMyCheckbox.CMTextChanged(var Message: TMessage);
begin
  inherited;
  if _MySetCap then Exit;
  FOriginalCaption := Caption;
end;

procedure TMyCheckbox.WMPaint(var msg: TWMPaint);
var
  BtnWidth: Integer;
  canv: TControlCanvas;
begin
  BtnWidth := GetSystemMetrics(SM_CXMENUCHECK);

  _MySetCap := True;
  if not (csDesigning in ComponentState) then
    Caption := '';
  _MySetCap := False;
  inherited;
  canv := TControlCanvas.Create;
  try
    canv.Control := Self;
    canv.Font := Font;
    SetBkMode(canv.Handle, Ord(TRANSPARENT));
    canv.TextOut(BtnWidth + 1, 2, FOriginalCaption);
  finally
    canv.Free;
  end;
end;

Answer 2

Oh, but you can!

Just place this before the declaration of your form :

TCheckBox = class(StdCtrls.TCheckBox)
public
  procedure CNCtlColorStatic(var Message: TWMCtlColorStatic); message CN_CTLCOLORSTATIC;
end;

This re-declaration of TCheckBox is now used at runtime as the type streamed from your form's DFM. Now implement the message like this :

procedure TCheckBox.CNCtlColorStatic(var Message: TWMCtlColorStatic);
begin
  SetTextColor(Message.ChildDC, ColorToRGB(clRed)); // or RGB(255,0,0));
  SetBkMode(Message.ChildDC, TRANSPARENT);
  Message.Result := GetStockObject(NULL_BRUSH);
end;

This traps the WM_CTLCOLORSTATIC message and changes the text color to red. This works in non-themed mode for me (using WinXP classic) - but not in themed mode.

You should know that in order to let themed controls send you this message, the control should supply the DTPB_USECTLCOLORSTATIC flag to the Theme-drawing API's. Sadly, that's not default behaviour, and I don't know how to do it either. Look at this question too.

Answer 3

Here's how I solved this in my app:

1. Remove the caption from the checkbox and make it smaller--just big enough to show the actual checkbox without the caption.
2. Put a TLabel next to the checkbox to act as the caption.
3. In the Label's OnClick event, toggle the state of the checkbox.
4. If the label has an Alt+letter keyboard accelerator, make the form handle the CM_DIALOGCHAR message. Copy the message handler from the TLabel source code and add a line to toggle the state of the checkbox.

It's not a real checkbox, and it's a bit more work than I'd like, but it works well enough in my app (which has only one checkbox that needs this treatment).