Attach Instrument to script

[tonynt]

Hello,

I´m working with parameters for years in NT7 using for doubles, ints and strings. All works ok.

Today I tried to use the string in parameters also for adding instruments so that we dont need to change it in the code. But when enabling the script I get the error-message

14.06.2019 03:51:02 Strategy The strategy 'TxMultiLSv12/64276884a61e42b8b5fac9e16171dd7b' has called the Add() method with an invalid instrument. Either 'instrument1' does not exist in the Instrument Manager or the specified exchange has not been configured.

Of course instrument1 doest not exist, but in parameters I fill eg NQ 06-19 and its causing the message.

Is there something special when adding instruments with string from parameters to Initialize?

Thank you!
Tony

[NinjaTrader_PaulH]

Hello tonynt,

Thanks for your post.

Please show the line of code where you have specified Instrument1 and then the line that shows the Add() method with instrument1.

Thank-you.

[tonynt]

Hello Paul,

thank you for your reply. Please see attached the screenshotsof the script in NT7.

Thank you!
Tony

[NinjaTrader_PaulH]

Hello tonynt,

Thanks for your reply.

In the add() statement you are adding the string "instrument1" which is being taken as the literal instrument name and what you need would be the variable named instrument1 that is a string with the instrument name that you are inputting. IE change Add("instrument1", PeriodType.Minute, 1) to Add(instrument1, PeriodType.Minute, 1)

[tonynt]

Hello Paul,

thank you for your reply. Now NT shoots me a message when I have one of the instruments parameter empty. How can we do when we have 4 instruments in parameters but only want to use 3 this day to avoid this error message from empty parameter.

Thank you!
Tony

[NinjaTrader_PaulH]

Hello tonynt,

Thanks for your reply.

You are setting the variables with the string that is the same name as the variable so you can use that in an if statement:

if (instrument4 != "instrument4") // making the assumption that if the variable instrument4 does not contain "instrument4" it must contain a legit instrument name
Add(instrument4, PeriodType.Minute, 1);

NOTE: If you do not add a 4th instrument, make sure you account for this in your OnBarUpdate() because if you have references to that 4th instrument and no data then you will get object not found type errors.