NullReferenceException in OnRender

[sidlercom80]

Hi, In OnRender I run this code:

-------here in OnRender()--------------
if (Position.MarketPosition != MarketPosition.Flat && !isPositionClosedXSendToMarket && chartTraderSL.Count > 0)
TriggerCustomEvent(o =>
{
   foreach (var item in chartTraderSL.ToArray())
[COLOR=#e74c3c]DrawOrderLineSL[/COLOR](item.Value.Order, chartControl, chartScale, item.Key, item.Value.OpenLoss, item.Value.TickValue);
}, null);


---------here in [COLOR=#e74c3c]DrawOrderLineSL[/COLOR]---------
var newValueWidth = new StopLoss { OrderLabelLayoutWidth = rectTextOrderLabelSL.Width + rectQtyOrderLabelSL.Width};

chartTraderSL.AddOrUpdate(orderId, newValueWidth, (key, oldValueWidth) =>
{
   if (newValueWidth.OrderLabelLayoutWidth != oldValueWidth.OrderLabelLayoutWidth)
        oldValueWidth.OrderLabelLayoutWidth = newValueWidth.OrderLabelLayoutWidth;

   return oldValueWidth;
});

sometimes i get a NullReferenceException. can anyone tell me what might be throwing this in the code and how best to fix it?

04.03.2021 09:27:34:000 > [SidiSystemBase][DrawOrderLineSL]-[ERROR]-System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
bei NinjaTrader.NinjaScript.Strategies.StopLoss.Equals (StopLoss other)
bei System.Collections.Generic.GenericEqualityComparer `1.Equals(T x, T y)
bei System.Collections.Concurrent.ConcurrentDictionary `2.TryUpdate(TKey key, TValue newValue, TValue comparisonValue)
bei System.Collections.Concurrent.ConcurrentDictionary `2.AddOrUpdate(TKey key, TValue addValue, Func`3 updateValueFactory)
bei NinjaTrader.NinjaScript.Strategies.SidiSystemBase. DrawOrderLineSL(Order order, ChartControl chartControl, ChartScale chartScale, String orderId, Double openProfit, Double tickValue) 

[NinjaTrader_Jesse]

Hello sidlercom80,

Thank you for the post.

Based on the error mentioning a ConcurrentDictionary and you are using what appears to be a dictionary I would guess it may be the chartTraderSL variable. You could add a condition like:

if(chartTraderSL != null)
{
    chartTraderSL.AddOrUpdate(orderId, newValueWidth, (key, oldValueWidth) => {
      if (newValueWidth.OrderLabelLayoutWidth != oldValueWidth.OrderLabelLayoutWidth) oldValueWidth.OrderLabelLayoutWidth = newValueWidth.OrderLabelLayoutWidth;
        return oldValueWidth;
    });
}

I look forward to being of further assistance.