Hello dear support.

I would like to create an indicator that indicates best ask volumes (via histogram).
When I receive input data array (PRICE type) I can access to such fields: open, close, high, low, volume (source: https://www.dukascopy.com/wiki/#Indicator_API:_InputParameterInfo). The volume field contains only best bid volumes.
Is there a way to receive in indicator full market depth information or best ask volumes?

Indicators receive only the best Bid/Ask price. You can only receive greater depth in strategy real-time run in the IStrategy.onTick method.

Did you mean Bid/Ask volumes?

As I understand, I receive bid or ask volumes (in volume field) in indicator depends on which kind of price was selected on the chart window. Am I right?
Or I can manually choose (in the indicator's code) which volume (bid or ask) I'll receive in indicator?

This applies both to prices and volumes.
Yes.
You can set to the input parameter which offer side you want to receive, for instance:

             new InputParameterInfo("Input data Ask", InputParameterInfo.Type.PRICE){{                 
                 setOfferSide(OfferSide.ASK) ;
             }}

That's exactly what I needed.

Thank you for your answers and help. Issue was fixed.