Place-a-short-stop-order-if-long-fails

Using bar + 2 in a signal is actually a peeking error in Version 6 (it would have created a Position in the backtest one bar ahead of when it was actually possible).

But ignoring that, the idea is to prioritize the Buy over the Short if both signals could have occurred on the same bar. To do it, you need to peek ahead. WL (Version 8) doesn't allow you to peek unless you try hard to do it. This would be one of those situations.

Below is framework you can use. It will avoid the peeking error, always prioritizing the Buy in the backtest. On the last bar, it will generate both signals to send to the broker - which the broker may not allow and result in an order error.

In any case, for live trading you'll probably need to enable "Use Live Positions" in the Trading Preferences to make sure you're dealing with the correct position type.

CODE:
using System;
using WealthLab.Backtest;
using WealthLab.Core;
using WealthLab.Data;
using WealthLab.Indicators;
using WealthLab.DataExtensions;
using System.Collections.Generic;

namespace WealthScript3 
{
    public class Strategy12415 : UserStrategyBase
    {
      Parameter _lookback;
      IndicatorBase _highest;
      IndicatorBase _lowest;
      
      public Strategy12415()
      {
         _lookback = AddParameter("Lookback", ParameterType.Int32, 20, 10, 30, 2); 
      }

      
        public override void Initialize(BarHistory bars)
        {
         _highest = Highest.Series(bars.High, _lookback.AsInt);
         _lowest = Lowest.Series(bars.Low, _lookback.AsInt);
//         PlotIndicatorLine(_highest, WLColor.Green, 1, LineStyle.Dotted);
//         PlotIndicatorLine(_lowest, WLColor.Red, 1, LineStyle.Dotted);
         PlotStopsAndLimits(3);
         
         StartIndex = _lookback.AsInt; 
        }


        public override void Execute(BarHistory bars, int idx)
        {
         Position p = LastPosition;
         
            if (p == null || !p.IsOpen)
            {
            bool buyFilled = false;

            // don't peek for the fill on the last bar to avoid error
            if (idx < bars.Count - 1)
               buyFilled = bars.High[idx + 1] >= _highest[idx];
            
            PlaceTrade(bars, TransactionType.Buy, OrderType.Stop, _highest[idx], "Long");
            
            if (!buyFilled)
               PlaceTrade(bars, TransactionType.Short, OrderType.Stop, _lowest[idx], "Short"); 
            }
            else
            {
            if (idx + 1 - p.EntryBar >= 1)
               ClosePosition(p, OrderType.Market, 0, "Time based");
               
            if (p.PositionType == PositionType.Long)
            {
               //handle the long position               
            }
            else
            {
               //handle the short position               
            }
            
            }
        }
    }
}