Unhandled exception

[Trino]

I have the same problem with a stopLoss Order. I tried everything from these links

https://ninjatrader.com/support/forum/forum/ninjatrader-8/indicator-development/103524-how-to-get-thread-safe-collection-of-orders

https://ninjatrader.com/support/helpGuides/nt8/en-us/?multi-threading.htm

but could not find a solution.

[NinjaTrader_ChelseaB]

Hello Trino,

To confirm, the exact error message you are getting is 'Unhandled exception: Collection was modified; enumeration operation may not execute'?

If you comment out the SetStopLoss() or Exit() method does the error stop?

[Trino]

Yes, commenting out the stopLoss eliminates the error, but (obviously) the strategy does not function then.

[NinjaTrader_Jim]

Hello Trino,

It is not exactly clear how you are hitting this error.

Chelsea's recommendation for accessing the Account.Orders collection involves adding a lock() to protect the code that accesses the collection to avoid this error.

Are you accessing the Account.Orders collection and hitting this error? If so, please be sure to use a lock() to protect the code that accesses the collection.

If this is not the case, could you attach a barebones example similar to the following that demonstrates how you are hitting this error?

SampleMonitorStopProfit - https://ninjatrader.com/support/help..._and_profi.htm

I look forward to being of further assistance.

[Trino]

I use a strategy from the Wizard. The line that produces the error while back testing is

ExitLongStopLimit(Default.Quantity, 0, 0, “”, “”);

If I comment that line out, the error disappeared.




What should be inside the brackets of the lock() command: (?)

lock() ExitLongStopLimit(Default.Quantity, 0, 0, “”, “”);

still produces the error.

Thank you for your patience.

[NinjaTrader_Jim]

Hello Trino,

Are you able to reproduce this error using a Strategy Builder created strategy that has not been unlocked?

If so, could you attach an export of this strategy with some steps that I can take to hit this error in the Strategy Analyzer?

If this is a an error that you have encountered with an unlocked strategy, could you attach a reduced version that only depicts this issue and could you also include a screenshot showing the exact context of the error you are receiving?

Please follow the instructions below to attach an exported NinjaScript strategy.

Exporting as Source Code - https://ninjatrader.com/support/help...tAsSourceFiles

Attaching a screenshot

To send a screenshot with Windows 7 or newer I would recommend using Window's Snipping Tool.

Click here for instructions

Alternatively to send a screenshot press Alt + PRINT SCREEN to take a screenshot of the selected window. Then go to Start--> Accessories--> Paint, and press CTRL + V to paste the image. Lastly, save as a jpeg file and send the file as an attachment.

Click here for detailed instruction

I look forward to your reply.