public async Task GetPositions() { // Account positions TTAccount account = await _client.GetAccountAsync(); List <TTPosition> positions = null; if (account.AccountingType == TTAccountingTypes.Net) { if (string.IsNullOrEmpty(PositionId)) { positions = await _client.GetAllPositionsAsync(); } else { try { TTPosition position = await _client.GetPositionAsync(PositionId); positions = new List <TTPosition>(new[] { position }); } catch (Exception) { } } } Positions = positions != null ? new ObservableCollection <TTPosition>(positions) : null; }