Use Application/Browser Activity giving error for dynamic selector

Am trying to pass the selector in the string variable for the Use Application/Browser Activity from UiAutomationNext.Activities Packaes, it is giving the error.
Instead if am passing the variable in the below format it is accepting “”+selector+""

have a look here:

@ppr Thanks for referring the article , My question is not related to the UiAutomation Activities it is related to the UiAutomationNext.Activities

taken from here:

doing it as mentioned

May be i have conveyed wrongly about my query. I want to pass the entire selector in a string variable not the single attribute of it

While am trying to achieve this using the Activity of UiAutomationNext.Activities Package(Use Application/Browser)

When am replacing the variable in the selector property of Use Application/Browser, it is showing the validation error to the other activities places under it.

If place the Variable in the format of “”+Variable+"" its working in version (20.6,0 - Preview) and below this version even this is showing as the error

Hope am clear with my query.

As am working on the test cases the URL and attach browser selector changes from Environment to environment(Dev to QA to UAT)