Mengubah warna komponen aktif

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Edit3: TEdit;
Edit4: TEdit;
Edit5: TEdit;
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
procedure DoActiveControl(Sender: TObject);
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
OldControl: TComponent;

implementation

{$R *.dfm}

procedure TForm1.DoActiveControl(Sender: TObject);
begin
if assigned(OldControl) then
begin
(OldControl as TEdit).color := clWhite;
(OldControl as TEdit).font.color := clBlack;
end;
if activeControl is TEdit then
begin
(activeControl as TEdit).color := clRed;
(activeControl as TEdit).font.color := clYellow;
OldControl := activeControl as TEdit;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
screen.OnActiveControlChange := DoActiveControl;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
// mencegah terjadinya GP Fault
screen.OnActiveControlChange := nil
end;

end.