Object reference not set to an instance of an object Error

[aligator]

Dear support:

I have an indicator that caculates the ratio between two instruments and use the value as a dataseries to create an oscilator. The oscilltor is ploted most of the time. But if I change to a different time frame, a different instrument, or even change the periods parameters for the oscillator will not plot and the an error is generated:

"Object reference not set to an instance of an object."

I have made sure that CurrentBar under OnBarUpdate is not < Periods but the issue persist.

I could not find any references in the forum addressing this error for plotting indicators. I have seen some references regarding correlation indicator with similar issues, but did not help.

Any chance that you could provide some info on what might be causing this error.

Many thanks.

[NinjaTrader_BrandonH]

Hello aligator,

Thanks for your post.

The error is advising that something you are accessing has not been created at the time you are accessing it. There is no specific thing I can advise regarding the source of the error.

To determine what the source of the error is you will need to debug your indicator. This is typically done with print statements added to your code to send a print output to the New > Ninjascript Output window.

As you do not know where the error is, you would add a print statement every few lines of code that print out the values being used in that section of code and then observe the output window when you use the indicator. The last print statement value shown in the output window would indicate the error occurs after that print statement, you can then add further print statements to zero in on the offending code.

Here is a link to our tips on debugging: https://ninjatrader.com/support/help...script_cod.htm

Below is a link to a forum post that demonstrates how to use prints to understand behavior.

https://ninjatrader.com/support/foru...121#post791121

Let us know if we may assist further.

[aligator]

Thanks NinjaTrader_BrandonH


SOLUTION: In case others have similar issues, my specific problem was caused by using custom brushes for BackBrushes whithout using a BackBrushes[0].Freeze(); statetement. Not freezing the custom brush was sometimes causing problems in muli-threading processes and the indicator was not plotted. Now everything is fixed and fine.

I was easier to go through logic and rewrite the indicator than debugging using write statements.

There must be an easier way, for example, if NinjaScript detects custom brushes are used simply include a Freeze statement. This idea can be applied to other situations where fixes can be internally used to avoid mind numbing errors.

Cheers!.