procedure TForm1.Button1Click(Sender: TObject);
begin
//覆盖任务栏
Self.BorderStyle := bsNone;
Self.Left := 0;
Self.Top := 0;
Self.Width := Screen.Width;
Self.Height := Screen.Height;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
//保留任务栏
Self.BorderStyle := bsNone;
Self.Left := Screen.WorkAreaLeft;
Self.Top := screen.WorkAreaTop;
Self.Width := Screen.WorkAreaWidth;
Self.Height := Screen.WorkAreaHeight;
end;