Finding first bar in the IDataSeries

[afshinmoshrefi]

How can I find the oldest bar accessible in IDataSeries?

[NinjaTrader_Lance]

Hello,

You could use this

myDataSeries[CurrentBar];

CurrentBar will give the total number of bars

http://www.ninjatrader.com/support/helpGuides/nt7/index.html?currentbar.htm

Please let me know if I can be of further assistance.

[afshinmoshrefi]

That makes Sense. Thank you

[koganam]

How can I find the oldest bar accessible in IDataSeries?

That depends on what your IDataSeries represents. For a Plot, that would always be PlotID[CurrentBar]. For any other kind of dataseries that you define, your maximum valid value will be [255], as by default only 256 values are kept. If you want to ensure that [CurrentBar] correctly indexes your value, then you have to make sure that the dataseries uses the infinite maxbars overload.

[afshinmoshrefi]

I thought 256 values are cached, but accessing other bars would fetch the data from the source. Is that correct or would I get an error when trying to access bars that are more than 256 bars in the past?

[koganam]

I thought 256 values are cached, but accessing other bars would fetch the data from the source. Is that correct or would I get an error when trying to access bars that are more than 256 bars in the past?

You will not get an error: you will just get values that may not be valid. At least that is what is implied by the verbiage in the help text. Look it up.

EDIT: I stand corrected. You will get an error. I just realized that I had never done it because I never need to see that far back to make a decision, in code or in life.

[NinjaTrader_Lance]

Hello,

You should get an error if calling a bar greater than 255 unless
MaximumBarsLookBack = MaximumBarsLookBack.Infinite;

Will look something like this if not:
Error on calling 'OnBarUpdate' method for indicator 'YourIndicator' on bar 256: barsAgo needed to be between 0 and 255 but was 256