private void processingPDF(Position[] position, string pdfText, string path) { Samo.calcScore(position, pdfText); List <TodoItem> temp = pdfList.ItemsSource as List <TodoItem>; if (temp == null) { pdfList.ItemsSource = data.bestItem(records.Position, path); } else { List <TodoItem> newList = new List <TodoItem>(temp); newList.Add(data.bestItem(records.Position, path)[0]); pdfList.ItemsSource = newList; } }