Need help on Stochastics(param).K[n]

[shielint]

I try to code a stochastics divergence indicator and seem to have a problem with the Stochastics() indicator. The following works fine:

public class StochDivergence : Indicator
{
protected override void Initialize()
{
Add(new Plot(Color.FromKnownColor(KnownColor.DarkGreen), PlotStyle.Line, "Plot0"));
CalculateOnBarClose = false;
Overlay = false;
PriceTypeSupported = false;
}
protected override void OnBarUpdate()
{
// +++++++++++++++++
Values[0].Set(Stochastics(3,5,2).K[0]); //<=== This line
// -------------------------------
}
}

Above code works fine, stochastics %K is displayed on the chart..
But if I change the K[0] to K[1] or other non-zero positive integer value, nothing is displayed on the chart. Stochastics().D[] has the same problem. It seems I can only access current bar's %D abd %K. (According to the manual, D[1] or K[3] should work.)

What do I do wrong? Please help.

Thanks

[NinjaTrader_Bertrand]

Welcome to our forums - you just miss a simple check at the OnBarUpdate() start to make sure only valid bars are accesssed. Your indicator would likely throw an error to the log if you tried accessing prior bars -

http://www.ninjatrader-support2.com/vb/showthread.php?t=3170

[shielint]

Thank you very much for the help. It makes perfect sense.