Simple S&R indicator NOT Showing up, NOT Working

[MohammedAmine]

Hello NT Team,

I made a small and simple S1R Indicator that each time makes new Support and Resistance levels based on previous candles, but it seemds it doesn't work I dono why

this is the code :

namespace NinjaTrader.NinjaScript.Indicators.TheGM
{
    public class TheGMSupportandResistance : Indicator
    {
        protected override void OnStateChange()
        {
            if (State == State.SetDefaults)
            {
                Description                                    = @"Enter the description for your new custom Indicator here.";
                Name                                        = "TheGMSupportandResistance";
                Calculate                                    = Calculate.OnBarClose;
                IsOverlay                                    = 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;
            }
            else if (State == State.Configure)
            {
            }
        }

        protected override void OnBarUpdate()
        {
            if (Low[0] < Low[1])
                Draw.HorizontalLine(this, "Support", Low[0]-TickSize, Brushes.Green);

            if (High[0] > High[1])
                Draw.HorizontalLine(this, "Resistance", High[0]+TickSize, Brushes.Red);
        }
    }
}​

can you tell me what is wrong please ? Thank you

[Tasker-182]

Look at the “log” tab of the NinjaTrader control center and review the error messages.

when your indicator loads it executes starting with the first historical bar therefore there is no previous bar Low[1] or High[1]. Check the help guide on how to use CurrentBar to prevent processing until CurrentBar is greater than 1 at least.

[MohammedAmine]

Thank you very much, I added

if (CurrentBar > 0)

and seems that it works, but sometimes in some indicators I see in code

if (CurrentBar == 0) else ....

what does it mean ?

Thank you

[NinjaTrader_ChrisL]

Hi Mohammed, thanks for posting. When a script accesses bars back, the script needs to make sure there are enough bars on the chart before accessing E.g. High[1]. If you access High[1] when CurrentBar == 0, it will fail, so we have code at the top of OnBarUpdate that makes sure there is at least 2 bars on the chart.