Unable to plot previous bar values

[Chris.M]

Hi,

I'm trying to plot values from previous bars within OnBarUpdate() however nothing is being plotted when I access bar values from previous bars:

Value[0] = High[1] - Low[1];

Accessing the current bar works fine:

Value[0] = High[0] - Low[0];

Below is a basic example indicator trying to plot the previous bar's range.
Should this not plot the previous bars range? Or am I missing something?

public class PrevRange : Indicator
{
	protected override void OnStateChange()
	{
		if (State == State.SetDefaults)
		{
			Description									= @"Enter the description for your new custom Indicator here.";
			Name										= "PrevRange";
			Calculate									= Calculate.OnEachTick;
			IsOverlay									= false;
			DisplayInDataBox							= true;
			DrawOnPricePanel							= true;
			DrawHorizontalGridLines						= true;
			DrawVerticalGridLines						= true;
			PaintPriceMarkers							= true;
			ScaleJustification							= NinjaTrader.Gui.Chart.ScaleJustification.Right;
			//Disable this property if your indicator requires custom values that cumulate with each new market data event. 
			//See Help Guide for additional information.
			IsSuspendedWhileInactive					= true;
			AddPlot(new Stroke(Brushes.Orange, 2), PlotStyle.Bar, "PrevRangePlot");
		}
		else if (State == State.Configure)
		{
		}
	}


	protected override void OnBarUpdate()
	{
		[B]Value[0] = High[1] - Low[1];[/B]
	}

	#region Properties

	[Browsable(false)]
	[XmlIgnore]
	public Series<double> PrevRangePlot
	{
		get { return Values[0]; }
	}
	#endregion
}

Thanks,
Chris

[koganam]

Hi,

I'm trying to plot values from previous bars within OnBarUpdate() however nothing is being plotted when I access bar values from previous bars:

Value[0] = High[1] - Low[1];

Accessing the current bar works fine:

Value[0] = High[0] - Low[0];

Below is a basic example indicator trying to plot the previous bar's range.
Should this not plot the previous bars range? Or am I missing something?

public class PrevRange : Indicator
{
	protected override void OnStateChange()
	{
		if (State == State.SetDefaults)
		{
			Description									= @"Enter the description for your new custom Indicator here.";
			Name										= "PrevRange";
			Calculate									= Calculate.OnEachTick;
			IsOverlay									= false;
			DisplayInDataBox							= true;
			DrawOnPricePanel							= true;
			DrawHorizontalGridLines						= true;
			DrawVerticalGridLines						= true;
			PaintPriceMarkers							= true;
			ScaleJustification							= NinjaTrader.Gui.Chart.ScaleJustification.Right;
			//Disable this property if your indicator requires custom values that cumulate with each new market data event. 
			//See Help Guide for additional information.
			IsSuspendedWhileInactive					= true;
			AddPlot(new Stroke(Brushes.Orange, 2), PlotStyle.Bar, "PrevRangePlot");
		}
		else if (State == State.Configure)
		{
		}
	}


	protected override void OnBarUpdate()
	{
		[B]Value[0] = High[1] - Low[1];[/B]
	}

	#region Properties

	[Browsable(false)]
	[XmlIgnore]
	public Series<double> PrevRangePlot
	{
		get { return Values[0]; }
	}
	#endregion
}

Thanks,
Chris

You cannot access High[1] until there are at least 2 bars on the chart. You want to use an escape condition:

if (CurrentBar < 1) return;

before your code accessing the bars.

If you look in your log, you will see an error message: "You are accessing an index with a value that is invalid since its out of range. i.e. accessing a series [barsAgo] with a value of 5 when there are only 4 bars on the chart." If you search the forum on that error message, you will find many answers along the same lines that I have given above, some more explanatory than others.

The log is always the first place you should look for error messages when things do not go as you expect.

[Chris.M]

Indeed the error was present in the log and I was missing the escape condition.

Thank you very much koganam.