Color bar based on volume condition

[Adrift]

Hello,

I am trying to color each bar based on a simple condition: if the volume of that bar is greater of the previous bar volume.
I have tried this:

protected override void OnBarUpdate()
{
if (Volume[0] > Volume[1])
   BarBrush = Brushes.Goldenrod;
}

it compiles but when I add it to the chart it does nothing. What am I missing?

[Adrift]

I noticed in the log section this error: Error on calling OnBarUpdate method on bar 0

So I added a fix:

protected override void OnBarUpdate()
{
if( CurrentBar < 1 )
  return;

if (Volume[0] > Volume[1])
  BarBrush = Brushes.Goldenrod;
}

Now the indicator works. Please let me know if there is a better way to avoid this error.

[NinjaTrader_ChelseaB]

Hello Adrift,

Calling Volume[1] with an index of 1 bar ago when CurrentBar is 0, will cause an index error. There isn't 1 bar ago on the first bar. CurrentBar would need to be equal to or greater than 1 so that there would be a bar 1 bar ago.

Below is a link to a forum post on indexing errors.

https://ninjatrader.com/support/forum/forum/ninjatrader-8/indicator-development/1046200-indicator-that-calculate-in-different-chartime?p=1048513#post1048513