public void TrelloData(Trello data) { data.ShowValues(); var logs = getLogs().ToList(); logs.Add(data); using (var outputStream = System.IO.File.OpenWrite(JsonFileName)) { JsonSerializer.Serialize <IEnumerable <Trello> >( new Utf8JsonWriter(outputStream, new JsonWriterOptions { SkipValidation = true, Indented = true }), logs ); } }