Exposing a non DataSeries property in an indicator

[tquinn]

Is there a way in an indicator to have a DataSeries which is made public but is not plotted?

Example, HeikinAshi, I would like to assign a "bias" based on the body color, +1 for Close>Open, -1 for the opposite, which could be accessed from a strategy.

If this is done using Add(new plot) it plots a line at +-1 which messes up the scale. Of course the AutoScale can be set to false. I was wondering if there was a more elegant approach.

[NinjaTrader_Ray]

Good question Tom, absolutely there is a more elegant approach. You will want to add a property to your strategy.

Following is a partial sample code:

// Under variables
private bool bullish = false;

//Within OnBarUpdate()
bullish = Close[0] > Open[0] ? true : false;

// Under properties, create the public property that can be accessed from the strategy
public bool Bullish
{
get
{
Update();
return bullish;
}
}



Calling the Update() method is a key step. Indicators embedded in a strategy are optimized andonly call their OnBarUpdate() method when the indicator is called from the strategy, not every bar or tick. The indicator knows that when a DataSeries value is being accessed, it needs to call the OnBarUpdate() method. Since all you need is to know when a value is true or false, there is not need to store this data in a DataSeries object so we just create a basic property. To ensure this property has the most current value, we call the Update() method withing the property getter to force the indicator to call the OnBarUpdateI() method.


Ray

[tquinn]

If I wanted a DataSeries with no plot then:

// Under variables
private DataSeries noPlotData;

//Within Initialize()
noPlotData = new DataSeries(this);

//Within OnBarUpdate()
NoPlotData = { expression}

// Under properties, create the public property that can be accessed from the strategy
public DataSeries NoPlotData
{
get
{
// Update(); // Not used for series ???
return noPlotData;
}
}

[tquinn]

I assume this is need for backtesting?

[NinjaTrader_Ray]

Yes, same principlesapply.