API Delphi

unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
function IsActiveDeskTopOn:Boolean;
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
function TForm1.IsActiveDeskTopOn:Boolean;
var
Hd: HWND;
begin
Result := False;
Hd := FindWindow( Pchar('Progman'), nil);
Hd := FindWindowEx( hd, 0, 'SHELLDLL_DefView', nil);
Hd := FindWindowEx( hd, 0, 'Internet Explorer_Server', nil);
if hd = 0 then
Result := False
else
Result := True;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
if IsActiveDeskTopOn then
showmessage('Active Desktop is ON')
else
showmessage('Active Desktop is OFF');
end;
end.