Error: Object reference not set to an instance of an object.

[coopgrafik]

Hello,

I have a strategy that seems to be working for the most part: it will trade on a historical playback. However, if I try to run it in the strategy analyzer it throws out the error, "Error on calling 'OnBarUpdate' method on bar 2: Object reference not set to an instance of an object."

1. I have searched high and low on the support forum for a similar error. The advice is usually that there is a BarsAgo called somewhere that does not exist yet. However, I am not using this method so I'm hoping with your experience you'll be able to spot my mistake.

2. I also am using EnterLongLimit() in my code which of course opens the order object can of worms. I don't think I'm doing my orders correctly. I find that the order, if not triggered, will close on the next bar. Also, if I scale in with another order by hand I will get closed out of both orders. I have read the docs and while right up front it states this is advanced, I have to humbly say that I wish there were more examples of how the methods work together holistically. The documentation is on a very atomic level. This method does this. It has potentially 4 arguments. Here is one cold line of code that is totally unassociated with the other methods you would most likely be used in conjunction. Good luck! lol. As the developer switches gears into the unmanaged orders it would be so helpful to see the most popular examples of how the methods work together. I would think that most people want to replicate an ATM order programmatically so one of two "full" strategies that focus on the order methods would be gold!

The support here is thankfully wonderful. Again, just some humble and friendly questions and feedback from a new user who's getting his sea legs.

Code below. I'm dropping the entire thing for clarity.

#region Using declarations
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using System.Xml.Serialization;
using NinjaTrader.Cbi;
using NinjaTrader.Gui;
using NinjaTrader.Gui.Chart;
using NinjaTrader.Gui.SuperDom;
using NinjaTrader.Gui.Tools;
using NinjaTrader.Data;
using NinjaTrader.NinjaScript;
using NinjaTrader.Core.FloatingPoint;
using NinjaTrader.NinjaScript.Indicators;
using NinjaTrader.NinjaScript.DrawingTools;
#endregion

//This namespace holds Strategies in this folder and is required. Do not change it.
namespace NinjaTrader.NinjaScript.Strategies
{
public class CoopIM2 : Strategy
{
protected override void OnStateChange()
{
if (State == State.SetDefaults)
{
Description = @"Profit!";
Name = "CoopIM2";
Calculate = Calculate.OnBarClose;
EntriesPerDirection = 1;
EntryHandling = EntryHandling.AllEntries;
IsExitOnSessionCloseStrategy = true;
ExitOnSessionCloseSeconds = 30;
IsFillLimitOnTouch = false;
MaximumBarsLookBack = MaximumBarsLookBack.TwoHundredFiftySix;
OrderFillResolution = OrderFillResolution.Standard;
Slippage = 0;
StartBehavior = StartBehavior.WaitUntilFlat;
TimeInForce = TimeInForce.Gtc;
TraceOrders = false;
RealtimeErrorHandling = RealtimeErrorHandling.StopCancelClose;
StopTargetHandling = StopTargetHandling.PerEntryExecution;
BarsRequiredToTrade = 20;

// Disable this property for performance gains in Strategy Analyzer optimizations
// See the Help Guide for additional information
IsInstantiatedOnEachOptimizationIteration = true;
// My custom vars
MaxBarHeight = 1;
MinBarHeight = 1;
TradeEntryOffset = 1;
TradeTarget = 1;
TradeStopLossOffset = 1;
BarCompleteMin = 0.5;
AskImbalanceTarget = 1;
NumberOfContracts = 1;


}
else if (State == State.Configure)
{


SetProfitTarget(CalculationMode.Ticks, TradeTarget);
SetStopLoss(CalculationMode.Ticks, TradeStopLossOffset);

}
else if (State == State.DataLoaded)
{

} else if (State == State.SetDefaults) {

}

}


protected override void OnBarUpdate()
{
if (BarsInProgress != 0)
return;

if (CurrentBars[0] < 2)
return;


int numberOfImbalances = 0;
int imbalanceMultiple = 4;
double wickSize = High[0] - Low[0];
double barSize = Close[0] - Open[0];
double barRatio = Math.Round(barSize / wickSize, 2);
double CurrentBarHeight = ((High[0] - Low[0]) / TickSize) + 1; // Get the height of the current bar


// Instantiate volumetric bars
NinjaTrader.NinjaScript.BarsTypes.VolumetricBarsTy pe barsType = Bars.BarsSeries.BarsType as
NinjaTrader.NinjaScript.BarsTypes.VolumetricBarsTy pe;


// Create lists to hold the bid and ask data
List<long> myBid = new List<long>();
List<long> myAsk = new List<long>();


// Get the bid and ask into lists
for (int i = 0; i <= CurrentBarHeight; i++) // cycle through each tick level

{

long a = barsType.Volumes[CurrentBar].GetAskVolumeForPrice(High[0] -(i*TickSize)); // start at the top and work down
long b = barsType.Volumes[CurrentBar].GetBidVolumeForPrice(High[0] -(i*TickSize));

myBid.Add(b);
myAsk.Add(a);

}


if (CurrentBarHeight <= MaxBarHeight && CurrentBarHeight >= MinBarHeight) // is the bar not to big or too small

{

if (Open[0] == Close[0]) return; // stop everyhting if this is a doji

if (Open[0] < Close[0]) // If the direction of this bar long - GREEN BAR


{


if ( barRatio < BarCompleteMin ) return; // is the bar is too small in relation to the wick kill everything


for (int i = 1; i <= CurrentBarHeight-1; i++) // cycle through each tick level

{

if (myAsk[i-1] > ( myBid[i] * imbalanceMultiple) )

{

if (myAsk[i-1] != 0 && myBid[i] != 0) // scrub out any results with 0's as they don't count as an imbalance

{

numberOfImbalances++;

}


}


}


if (numberOfImbalances >= AskImbalanceTarget) { // do something if all conditions are met

//alerts: visual and audio
Draw.ArrowUp(this, @"AboveEMA Arrow up_1 " + Convert.ToString(CurrentBars[0]), true, 0, (Low[0] + (-2 * TickSize)) , Brushes.Yellow);
Draw.Text(this, "IM_tag"+CurrentBar, "IM:"+numberOfImbalances,0,Low[0]-1.5);
PlaySound(@"C:\Program Files (x86)\NinjaTrader 8\sounds\trade_imbalance.wav");

// lets buy some contracts!
string mySignal = "LongLimit"+CurrentBar;
double myEntryPrice = TradeEntryOffset * TickSize;
EnterLongLimit(NumberOfContracts, Close[0] - myEntryPrice, mySignal);


}


} else { // this is a RED BAR

if ( (barRatio * -1) < BarCompleteMin ) return; // is the bar is too small in relation to the wick kill everything

numberOfImbalances = 0;

for (int i = 1; i <= ((High[0] - Low[0]) / TickSize); i++) // cycle through each tick level

{


if (myBid[i] > ( myAsk[i-1] * imbalanceMultiple) )

{

numberOfImbalances++;


}


}

if (numberOfImbalances >= AskImbalanceTarget) { // do something if all conditions are met

Draw.Text(this, "IM_tag"+CurrentBar, "IM:"+numberOfImbalances,0,High[0]+1.5);
Draw.ArrowDown(this, @"AboveEMA Arrow down_1 " + Convert.ToString(CurrentBars[0]), true, 0, (High[0] + (+2 * TickSize)) , Brushes.Yellow);

// lets buy some contracts!
string mySignal = "ShortLimit"+CurrentBar;
double myEntryPrice = TradeEntryOffset * TickSize;
Print("The Close = " + Close[0] + " and the myEntryPrice = " + myEntryPrice + "TOTAL = " + Close[0]+myEntryPrice);
EnterShortLimit(NumberOfContracts, Close[0] + myEntryPrice, mySignal);

}


}


}

}

#region Properties
[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="MaxBarHeight", Order=1, GroupName="Parameters")]
public int MaxBarHeight
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="MinBarHeight", Order=2, GroupName="Parameters")]
public int MinBarHeight
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="TradeEntryOffset", Order=3, GroupName="Parameters")]
public int TradeEntryOffset
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="TradeTarget", Order=4, GroupName="Parameters")]
public int TradeTarget
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="TradeStopLossOffset", Order=5, GroupName="Parameters")]
public int TradeStopLossOffset
{ get; set; }

[NinjaScriptProperty]
[Range(0.1, double.MaxValue)]
[Display(Name="BarCompleteMin", Order=6, GroupName="Parameters")]
public double BarCompleteMin
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="AskImbalanceTarget", Order=7, GroupName="Parameters")]
public int AskImbalanceTarget
{ get; set; }

[NinjaScriptProperty]
[Range(1, int.MaxValue)]
[Display(Name="NumberOfContracts", Order=8, GroupName="Parameters")]
public int NumberOfContracts
{ get; set; }

#endregion


}
}

[NinjaTrader_Jesse]

Hello coopgrafik,

Thank you for the post.

You may need to add

if (barsType == null)
return;

The barsType can be null so the error you mentioned could be thrown if that object was null when you used it.

The easiest way to debug this type of error is to locate what line in OnBarUpdate is having the error first. You can use prints, place a print every few lines with a new number: Print("1"); etc. That will help you see where the script gets in execution when you hit the error. Once you know what line throws the error its much easier to debug.


For the limit order if they are expired after 1 bar that would be expected with the managed approach. You can either call the limit order method again to keep it active or use IsLiveUntilCancelled. That relies on you cancelling the orders with the order object.

EnterLongLimit(int barsInProgressIndex, bool isLiveUntilCancelled, int quantity, double limitPrice, string signalName)

https://ninjatrader.com/support/helpGuides/nt8/enterlonglimit.htm?zoom_highlightsub=enterlonglimit

For scaling in, when you do that manually for the platforms existing tools the strategy won't be able to handle that correctly. Closing positions manually will also terminate the strategy. If you want to manually interatct with the strategy its best to add custom buttons for those actions. There is a simple example of using the charts UserControlCollection here:

https://ninjatrader.com/support/helpGuides/nt8/usercontrolcollection.htm?zoom_highlightsub=usercontrol

https://ninjatraderecosystem.com/user-app-share-download/long-short-toolbar-buttons-2/

I look forward to being of further assistance.


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[coopgrafik]

Thanks for the leg up.

if (barsType == null) return;

This ended up killing the error!

However, using the Print("Line Number: 000"); trick I'm able to see that the script never actually makes it past this line.

To be honest I copy/pasted the lines of code below from a reply from a previous question so I'm not fluent in what is happening here.

Would it be possible to examine this area to see what I'm missing?

Thank you

// Instantiate volumetric bars
NinjaTrader.NinjaScript.BarsTypes.VolumetricBarsType barsType = Bars.BarsSeries.BarsType as
NinjaTrader.NinjaScript.BarsTypes.VolumetricBarsType;

if (barsType == null) return;

[NinjaTrader_Jesse]

Hello coopgrafik,

Are you selecting the volumetric bars in the backtest? If that is null that means the cast failed.

That line of code is casting the generic bars type to the specific volumetric type so you can see the volumetric methods and properties.

I look forward to being of further assistance.

[coopgrafik]

I was not. First time running a backtest on volumetric bars and just took them for granted. Oops!

Thanks for all the help.