Custom Indicator use ZigZag

[handlar]

Hi,

I get an error
Indicator 'zzTrend': Error on calling 'OnBarUpdate' method on bar 20: Object reference not set to an instance of an object.

Look in attach please, there is a simple indicator which use ZigZag indicator, but there is an error. I need help

private Series<double> zzH;
private Series<double> zzL;
private double DeviationValue = 0.14;

...

if (State == State.Configure) {
zzH = ZigZag(DeviationType.Points, DeviationValue, true).ZigZagHigh;
zzL = ZigZag(DeviationType.Points, DeviationValue, true).ZigZagLow;
}

and then in OnBarUpdate

I call
Print (Time[0].ToString()+" ZZH[0]="+ZigZag(DeviationType.Points, DeviationValue, true).ZigZagHigh[0] + " ZZH[2]="+ZigZag(DeviationType.Points, DeviationValue, true).ZigZagHigh[2]+"\n"+"ZZL[0]="+ZigZag(DeviationType.Points, DeviationValue, true).ZigZagLow[0] + " ZZL[2]="+ZigZag(DeviationType.Points, DeviationValue, true).ZigZagLow[2]);

and this code works fine

BUT

whte I change call to
Print (Time[0].ToString()+" ZZH[0]="+zzH[0] + " ZZH[2]="+zzH[2]+"\n"+"ZZL[0]="+zzL[0] + " ZZL[2]="+zzL[2]);

Then I get an error Indicator 'zzTrend': Error on calling 'OnBarUpdate' method on bar 20: Object reference not set to an instance of an object.

What do I wrong in this simple code example?

[NinjaTrader_PaulH]

Hello handlar,

Thanks for your post.

Your first print statement is calling the zigzag in line and while not a recommended practice, as you are providing all of the correct parameters will work.

The second print statement is calling the local instances of the indicator you created in State.Configure. The indicator method is better created in State.Historical, please see performance practices in the helpguide section here:https://ninjatrader.com/support/help..._practices.htm