Error about Extensions

Hi all,

I got the file from my friend.
I have this issues when open it on my computer.

When i check by this way, i can see name extensions “isNullOrEmpty” below.

Please help me in learn

Hi @AKY,

Use the below code


Thank you @arivu96
But i want to keep the code scource.
Can i fix with other way?


I see.
I just want to know the program error on my computer but not the other computer.
I do not want to edit anything, because I want to keep it to upload on the ochestrator for other computers to use to run.