Runtime error: Object reference not set to an instance of an object

lookingbackon

#1

4/5/2011 10:18 AM

Hello,
I just fine-tuned a strategy and the strategy can properly run basing on the existing symbol. But when I click other symbols for test, it can't work with the error remarks as below:

QUOTE:
Runtime error: Object reference not set to an instance of an object
At WealthLab.Strategies.BollingerBuyer.Execute()

What could be the problem?
Thanks

Cone

#2

4/5/2011 10:23 AM

Much too hard to guess without see the code.

lookingbackon

#3

4/5/2011 10:36 AM

So I need to put the strategy code here or just apply for a support ticket to send the code to you?
Thanks

BollingerBuyer, a pre-built strategy that came with WL, doesn't seem to be super secret code. It's best to start from Errors | Strategy > "Object reference not set to an instance of an object". Most likely cause is described in paragraph #2:

QUOTE:
If "Benchmark Buy & Hold" symbol is defined and enabled in the Wealth-Lab's Preferences dialog, Backtest Settings, you need to make sure that the symbol name is valid and could be found in your DataSets. Entering a symbol that does not exist is a popular reason for getting this error message in backtests.

lookingbackon

#5

4/5/2011 11:04 AM

It's not the cause of 2nd paragragh.

The draft code is as below. Would appreciate if you can help to address the problem.
Thanks

CODE:
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It's not the cause of 2nd paragragh.

The draft code is as below. Would appreciate if you can help to address the problem.
Thanks
[CODE]using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies
{
	public class BollingerBuyer : WealthScript
	{
		//Create parameters
		private StrategyParameter bbPeriod;
		private StrategyParameter bbStdDev;
		private StrategyParameter MAPeriod_1;
		private StrategyParameter MAPeriod_2;
		
		public BollingerBuyer()
		{

//Pushed indicator CreateParameter statements
			bbPeriod = CreateParameter("Bollinger Period", 80, 5, 400, 5);      
			bbStdDev = CreateParameter("Std Dev", 2, 1, 5, 0.25);  
			MAPeriod_1 = CreateParameter("MAPeriod_1", 10, 1, 100, 3); 
			MAPeriod_2 = CreateParameter("MAPeriod_2", 30, 1, 400, 3);
		}
		
		protected override void Execute()
		{
			//Obtain parameters values
			int bbPer = bbPeriod.ValueInt;
			double bbSD = bbStdDev.Value;
			
			DataSeries BBUp = BBandUpper.Series( Close, bbPer, bbSD );
			DataSeries BBDown = BBandLower.Series( Close, bbPer, bbSD );
			DataSeries BBUp_1 = BBandUpper.Series( Close, bbPer, bbSD );
			DataSeries BBDown_4 = BBandLower.Series( Close, bbPer, bbSD );
			DataSeries BBUp_2 = BBandUpper.Series( Close, bbPer, bbSD );
			DataSeries BBDown_5 = BBandLower.Series( Close, bbPer, bbSD );
			DataSeries BBUp_3 = BBandUpper.Series( Close, bbPer, bbSD );
			DataSeries BBDown_6 = BBandLower.Series( Close, bbPer, bbSD );
		
			PlotSeries(PricePane, BBDown, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, BBUp, Color.Blue, LineStyle.Solid, 1 );
	    	PlotSeries(PricePane, BBUp_1, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, BBUp_2, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, BBUp_3, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, BBDown_4, Color.Blue, LineStyle.Solid, 1 );
		    PlotSeries(PricePane, BBDown_5, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, BBDown_6, Color.Blue, LineStyle.Solid, 1 );
			
			DataSeries SMA_Close = SMA.Series(Close,MAPeriod_1.ValueInt);
			DataSeries SMA_Close_2 = SMA.Series(Close,MAPeriod_2.ValueInt);
			
			PlotSeries(PricePane, SMA_Close, Color.Blue, LineStyle.Solid, 1 );
			PlotSeries(PricePane, SMA_Close_2, Color.Green, LineStyle.Solid, 2 );
			
			SolidBrush shadowBrush = new SolidBrush(Color.FromArgb(50, Color.Silver));
			PlotSeriesFillBand(PricePane, BBUp, BBDown, Color.Silver, shadowBrush, LineStyle.Solid, 1);

for(int bar = GetTradingLoopStartBar(21); bar < Bars.Count; bar++)
			{
				if (IsLastPositionActive)
				{
					Position p = LastPosition;

if (p.EntrySignal.Contains("GroupLD|"))
					{
						if (CrossUnder( bar, SMA_Close, BBUp ))
						{
							SellAtMarket(bar + 1, p, "GroupLD");
						}
						else if (BBDown[bar] < BBDown[bar-2])
						{	if (Close[bar] < Math.Min( Low[p.EntryBar], Low[p.EntryBar - 1] ))
							SellAtMarket(bar+1, p, "Stop Loss,LD");
						}	
					}
					if (p.EntrySignal.Contains("GroupLU|"))
					{
						if (CrossUnder( bar, SMA_Close, BBUp_2 ))
						{
							SellAtMarket(bar + 1, p, "GroupLU");
						}

}

}
				else
				{

if(CrossOver( bar, SMA_Close, BBDown ))
					{
						BuyAtMarket(bar + 1, "GroupLD|");
					}
										
					if (SMA_Close[bar] > SMA_Close[bar-5])
					{	if ((BBDown[bar] < BBDown[bar-1]) && Close[bar] > LastPosition.EntryPrice)
					
						BuyAtMarket(bar + 1, "GroupLD|");
					}
					if (CrossOver( bar, SMA_Close, BBUp_1 ))
					{   if (Close[bar] > BBUp_1[bar])
						BuyAtMarket(bar + 1, "GroupLU|");
					}

}
			}

}
	}
}[/CODE]

Eugene

#6

4/5/2011 11:09 AM

Easy one:

CODE:
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That happens when if (!IsLastPositionActive) i.e. you have no open positions, so you're checking the entry price for a Position that does not exist yet.

lookingbackon

#7

4/5/2011 11:43 AM

Thanks.
Yes, it's the cause.
So,is it possible to conduct the comparison for:
the "close(bar)" and the "entry price"(or the close price of the BAR at which last position buy/short) for the last postion which was sold/covered already?

Eugene

#8

4/5/2011 11:53 AM

Yes, by including an extra check for Positions.Count > 0 and at the same time making sure that the Position's Active property returns false (e.g. if(!LastPosition.Active) ).

lookingbackon

#9

4/5/2011 10:44 PM

It works now.Thanks a lot.

tomphm

#10

9/13/2015 5:24 PM

Hello,

I got the following error message when running the code below. The compilation is okay. My understanding is that the error is due to using the 'buy/sell' statements within a function beside that of 'Execute ()' function. Please let me know what can be done to resolve this. Thanks for any help.

CODE:
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runtime_error.png

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Hello,

I got the following error message when running the code below.  The compilation is okay.  My understanding is that the error is due to using the 'buy/sell' statements within a function beside that of 'Execute ()' function.  Please let me know what can be done to resolve this.  Thanks for any help.

[img]https://www.wealth-lab.com/handlers/DownloadHandler.ashx?id=5935&password=5b0d595e7b374b8[/img]

[code]
using System;
using System.Collections.Generic;
using System.Text;
using WealthLab;
using WealthLab.Indicators;
using System.Drawing;

namespace WealthLabCompile
{
  class MovingAverageCrossover : WealthScript
  {
    //Create parameters
    private StrategyParameter slowPeriod;
    private StrategyParameter fastPeriod;

public MovingAverageCrossover()
    {
        fastPeriod = CreateParameter("Fast Period", 20, 1, 100, 1);
        slowPeriod = CreateParameter("Slow Period", 50, 20, 300, 5);      
    }

public void trade(DataSeries smaFast, DataSeries smaSlow, int fastPer, int slowPer)
		{
			for (int bar = Math.Max(fastPer, slowPer); bar < Bars.Count; bar++)
			{
				if (IsLastPositionActive)
				{          
					if (CrossUnder(bar, smaFast, smaSlow))
						SellAtMarket(bar + 1, LastPosition);
				}
				else
				{
					if (CrossOver(bar, smaFast, smaSlow))
						BuyAtMarket(bar + 1);
				}
			}
		}
		protected override void Execute()
		{
			//Obtain periods from parameters
			int fastPer = fastPeriod.ValueInt;
			int slowPer = slowPeriod.ValueInt;
      
			MovingAverageCrossover n = new MovingAverageCrossover();
			
			DataSeries smaFast = SMA.Series(Close, fastPer);
			DataSeries smaSlow = SMA.Series(Close, slowPer);
			
			PlotSeries(PricePane, smaFast, Color.Green, LineStyle.Solid, 2);
			PlotSeries(PricePane, smaSlow, Color.Red, LineStyle.Solid, 2);

n.trade(smaFast, smaSlow, fastPer, slowPer);

}
  }
}[/code]

Eugene

#11

9/13/2015 6:03 PM

Strategies aren't meant to be self-referenced or become recursive. If you have a good reason for doing what you're trying to do, feel free to ask in a new thread - because being the most unusual cause of typical, FAQ-like "Object reference not set to an instance of an object" error I've ever seen, it doesn't really belong here. Otherwise the solution is to not break what's working.

tomphm

#12

9/14/2015 1:40 AM

Thanks Eugene, I am not sure what you mean by 'self-reference' or 'recursive' in this case. The reason I use this approach is to make the program more modular and its flow more easier to understand. The function that open & close positions is part of a larger program and will be call many times depends on a number of conditions. Having it resides on a function beside the Main or Execute () seems to be cleaner and makes more sense. Thanks.

Eugene

#13

9/14/2015 2:27 AM

Thanks for the clarification Tom. In fact, your program is trying to be exactly what you're not sure about -- i.e. be recursive or reference itself. The concept of recursion is outside C# 101 but still you might want to google it. You're invited to discuss the modular approach to building WealthScript programs in a new (or more appropriate) forum thread. This is a topic of its own.

WEALTHPRO25

#14

9/13/2017 1:43 AM

i have the following code and it compiles but i get runtime error: object reference not set to an instance of an object, please help

CODE:
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Eugene

#15

9/13/2017 6:02 AM

The DataSet parameter of GetExternalSymbol is context sensitive:

CODE:
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Or simply don't use it (just like you do for "Bars b1"):

CODE:
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WEALTHPRO25

#16

12/9/2017 8:32 PM

i have been using this code with no issue and suddenly i have runtime error using symbol ^GSPC with yahoo provider, please help

CODE:
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the run time error is index is out of range must be non negative and less than size of collection,
also daily, weekly, quaterly and yearly chart work but monthly chart gives an error

runtime.png

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Color:

i have been using this code with no issue and suddenly i have runtime error using symbol ^GSPC with yahoo provider, please help

[code]using System;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;
using TASCIndicators;
using Community.Indicators;
namespace WealthLab.Strategies
{
	public class ReversingMACDSequel : WealthScript
	{
		protected override void Execute()
		{
			// Reversing MACD
			HideVolume();
			RevEngMACDSignal r = RevEngMACDSignal.Series( Close,12,26,9,false );
			PlotSeries( PricePane, r, Color.Blue, LineStyle.Dashed, 2 );
			// MACD and MACD signal
			DataSeries macd = MACD.Series( Close );
			DataSeries macdSignal = MACDEx_Signal3.Series( Close,12,26,9 );
			DataSeries macdHist = MACDEx_Histogram.Series( Close,12,26 );
			ChartPane MACDPane = CreatePane( 50, true, true );
			PlotSeries( MACDPane, macd, Color.Blue, LineStyle.Solid, 2 );
			PlotSeries( MACDPane, macdSignal, Color.Red, LineStyle.Solid, 2 );
			PlotSeries( MACDPane, macdHist, Color.Teal, LineStyle.Histogram, 2 );
            
			for(int bar = r.FirstValidValue; bar < Bars.Count; bar++)
			{
				if( CrossOver( bar, macdSignal, macd ) )
					SetBackgroundColor( bar, Color.FromArgb( 30, Color.Green ) );
				if( CrossUnder( bar, macdSignal, macd ) )
					SetBackgroundColor( bar, Color.FromArgb( 30, Color.Red ) );
                
				if (IsLastPositionActive)
				{
					if( macd[bar] > 0 )
						SellAtStop( bar+1, LastPosition, r[bar] );
				}
				else
				{
					if( macd[bar] < 0 )
						BuyAtStop( bar+1, r[bar] );
				}
			}
		}
	}
}[/code]

the run time error is index is out of range must be non negative and less than size of collection,
also daily, weekly, quaterly and yearly chart work but monthly chart gives an error

Eugene

#17

12/9/2017 8:46 PM

For possible reasons see Errors > Index was out of range. Most likely you have a broken chart drawing object on Monthly ^GSPC as the code runs for me just fine.