Uipath string null

Question

Does anyone know how to check for an unassigned string in uipath? Uipath seems to crash when an if statement looks for a null string. Not sure how to handle that. String.empty doesn't seem to work, and if the string is unassigned uipath stops logging and nothing happens.

Pressey

Answer 1

There are many different approaches and ideas, but – according to me – what you can do is:

1. Always make sure before to define any variable by default, initialize it with empty strings(""). So it will be easy to check it with equal operator as well.

2. The Other approaches you can take in Uipath is based on .Net So u can use it's Is Nothing.

3. You can also use .Net String.IsNullOrEmpty Method (String) Method.

Crescendo

Answer 2

To check if a string variable is Null, you need to use either an If or Decision activity. The condition of those should be:

a is Nothing

This will return true if variable a is null and false otherwise

Frederiksberg

Hey andra- when I do that uipath stops logging and crashes. I think maybe because it's not nothing or anything so to speak... – Pressey

Hi Dan, what version of UiPath are you using? I've tried to reproduce your problem and I am unable. Are you using a String variable or a Generic Value one? – Frederiksberg

V8 for uipath. Using a string variable. I fixed it by assigning all my strings as string.empty in the variables window – Pressey

Answer 3

Best way to check string has value or not -->

Herbert

Answer 4

These are some of the ways it can be checked.

1.

String.IsNullOrEmpty(yourString)

2.

yourString.Equals("")

3.

yourString.Equals(Nothing)

4.

yourString is Nothing

5.

String.IsNullOrWhiteSpace(yourString)

There are logical OR, AND and NOT to combine the different checks and they can clubbed together to check the best way to find out blank, null and whitespace string.

Parted

yourString.Equals("") or even yourString.Equals(String.Empty), would produce an exception if yourString is Nothing. Nr5, i.e. String.IsNullOrWhiteSpace(yourString), is the best choice. – Carpetbagger

Answer 5

You can compare the string using:

Convert.ToString(DBNULL.Value)

Ihram

Answer 6

We can check whether String is null with the following Syntax

String.IsNullOrWhiteSpace("Name_of_the_variable")

It will return boolean value

Torbart

Answer 7

My suggestion is using the following method in UiPath

An If/Decision activity with the condition string.IsNullOrEmpty() making use of the IsNullOrEmpty() method

Backman

Answer 8

The best and easiest way will be the following:

String.IsNullOrWhiteSpace(stringVariableName)

Barbed

This is the same as other answers – Generally