Code:

public

{ Public declarations }

procedure GrabScreen;

...

implementation

{$R *.DFM}

procedure TForm1.GrabScreen;

var

DeskTopDC: HDc;

DeskTopCanvas: TCanvas;

DeskTopRect: TRect;

begin

DeskTopDC := GetWindowDC(GetDeskTopWindow);

DeskTopCanvas := TCanvas.Create;

DeskTopCanvas.Handle := DeskTopDC;

DeskTopRect := Rect(0, 0, Screen.Width, Screen.Height);

Form1.Canvas.CopyRect(DeskTopRect, DeskTopCanvas, DeskTopRect);

ReleaseDC(GetDeskTopWindow, DeskTopDC);

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

GrabScreen;

end;