How to retrieve the value of the 'QuantityUpDown' and the state of the checkbox?

[aekzof]

Hello
I am currently creating my own addon, inspired by an example I found on the NinjaTrader forum: https://forum.ninjatrader.com/forum/...considerations.
The specific example I am using is called 'ChartTraderCustomButtonsExample_NT8,' which I downloaded from this link: https://forum.ninjatrader.com/filedata/fetch?id=909605.

In my strategy, I have tried to retrieve the value of the 'QuantityUpDown' and the state of the checkbox, but unfortunately, I am getting the following error message: 'OnBarUpdate method on bar 0: Object reference not set to an instance of an object.'
As a result, the strategy remains disabled and does not function correctly.
I have attached the addon and the strategy.
How can I resolve this issue?

Thank you in advance for the time you spend helping us

[NinjaTrader_BrandonH]

Hello aekzof,

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 as to the source of the error.

To determine what the source of the error is you will need to debug your strategy. 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 and then observe the output window when you apply the strategy. 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

You could view this help guide page for information and sample code about accessing QuantityUpDown in a custom NinjaScript: https://ninjatrader.com/support/help...tityupdown.htm

Here is a link to a forum thread containing an example script that my colleague Chelsea shared demonstrating the use of QuantityUpDown: https://forum.ninjatrader.com/forum/...830#post759830

[aekzof]

Hello
I work directly within the indicator without using a strategy. I have added a condition to check if the QuantityUpDown is null. Then,
I added 'ChartControl.Dispatcher.InvokeAsync((() =>' and everything is functioning without any issues.
However, I am not sure if this is the solution!

   protected override void OnBarUpdate()
//     Quantity_Selector = new NinjaTrader.Gui.Tools.QuantityUpDown();
        {

            if (Quantity_Selector != null)
            {

                ChartControl.Dispatcher.InvokeAsync((() =>
                {
                    Print("Quantity_Selector NOT null ");
                    Print("Strategy Quantity_Selector : " + Quantity_Selector.Value);
                }));
            }
            else
            {
                Print(CurrentBar + " "+ Time[0]);
                Print("Quantity_Selector = null ");

            }

    }​

[NinjaTrader_BrandonH]

Hello aekzof,

Thanks for your notes.

Yes, if you do not see errors occurring and everything is functioning without any issues then this would be a possible solution.

Please let us know if we may assist further on this matter.

[aekzof]

Hello
To make it work, I had two errors that were corrected by this script.
Thank you for your help.