IsNothing activity always giving negative output

[shekhawat.arjun1307]

Hi, i am using the IsNothing activity to create a condition to check if my string variable is empty or not but the if condition always enters the if-else and not if-then, no matter my variable is empty or not. For reference in the attached pic the loop always output - Decision_ + “is not empty”.

[prasath17 (Guru)]

@shekhawat.arjun1307 - When its empty and going to through the else loop, what is your message box output?

[shekhawat.arjun1307]

Yes it is displaying - is not empty

[Rakesh_Sampath]

Hi @shekhawat.arjun1307

Could you please try the below statement and update whether its working or not !!

String.IsNullOrWhiteSpace(stringVariableName)

Thanks !!

[shekhawat.arjun1307]

@Rakesh_Sampath It works, Thanks.

[jeevith (Jeevith Hegde, Ph.D.)]

Hi @shekhawat.arjun1307,

Although this thread has a solution, for people who are wondering why this did not work, here is a short explanation.

1. When you use IsNothing(VariableString) this will always return False. This happens because IsNothing method will only work if your VariableString is a Reference Type variable i.e., you explicitly have assigned Nothing to it. See Remarks section in this link.

2. When you have a Value Type VariableString, either the IsNullOrEmpty(VariableString) or String.IsNullOrWhiteSpace(VariableName) will work fine. A Value Type can also be for example an empty string ("").

For anyone wanting to know more about Value Type vs. Reference Type

Workflow for reference: IsNothingVs.IsNullOrEmpty.xaml (7.8 KB)

Hope this clears some doubts.