How to get the bitmap on a hidden TWinControl

Problem/Question/Abstract:

I want to get a bitmap from the Device Context of a TWinControl that is hidden. Is this possible? I know the handle, but GetDC, Canvas.copyrect etc. return the desktop image.

Answer:

procedure TForm1.Button2Click(Sender: TObject);
var
  FControlCanvas: TControlCanvas;
  FBitmap: TBitmap;
begin
  FControlCanvas := TControlCanvas.Create;
  try
    FControlCanvas.Control := StringGrid1;
    FBitmap := TBitmap.Create;
    try
      FBitmap.Width := FControlCanvas.Control.Width;
      FBitmap.Height := FControlCanvas.Control.Height;
      FBitmap.Canvas.CopyRect(Rect(0, 0, FBitmap.Width, FBitmap.Height), FControlCanvas,
        Rect(0, 0, FBitmap.Width, FBitmap.Height));
      Image1.Picture.Assign(FBitmap);
    finally
      FBitmap.Free;
    end;
  finally
    FControlCanvas.Free;
  end;
end;