Hi,

Error is occurring because you are trying to refresh the same list which is in for loop. While the list is being iterated you can't define/change the source. Instead of refresh, you can use a list filter action and add your condition(i.e. to check subject chosen in the dropdown ), and use the output of list filter to enable/disable the button. Hope this clarifies.

Hello Izao, 

Basically, what Puja is trying to indicate to you is that OS provides some System actions that allow you to manipulate Lists. In this case, she is recommending you Use the ListFilter one. In Reactive, you can use these actions in the Client or Server side :) 

Here is the documentation link here you can find more information about this:

• https://success.outsystems.com/documentation/11/reference/outsystems_language/data/data_types/list/
  
  

Best regards, 

Ana

Hello Izao, 

You need to use list filter action from system module through manage dependency to filter the list rather than refreshing the same aggregate which in output throwing the error of list was redefined while being iterated.

If you need more explanation on how to do the same, kindly let me know then I will definitely help you out will the demo oml of the same.

Thank & regards.

Hi Izao

You are refreshing the same list which is used for the forloop. when for loop iterating again you refreshing the same list that's why you getting error.

and why you need to refresh the aggregate if you want to disable the button use the Boolean variable and assign value.

Thanks,

Ravi Kumar

@Izao  still you are iterating the list again and again its looping so only you are getting the error if you don't mine can you share your OML we can get much clarity while looking into your code 

thanks and regards

Thank you, everyone, for your help. However, I have managed to solve this problem by assigning 'False' boolean to the save button variable after clicking on the save button.