ERROR: Assign Object reference not set to an instance of an object


I tried to add up the data from three columns and save the result in a fourth column (FValue). But I always get this exception:

Can you please help me?
Thank you :slight_smile:

In your assign activity, one of the variables are not initalised. Please check.

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Hi @mcLauge

Welcome to UiPath community buddy

Kindly check with the variables in the right side of the assign activity, as it might not have any values in it and this error occurs only because of that

you are almost done
Kindy check that and get back for any queries or clarification

Cheers @mcLauge

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Hello @mcLauge
welcome to our community
Before save the result in forth column.check all other three column have value or not.


One of the instances is probably null, try putting some random values to the first 3 columns before the Assign activity to check this.

I want to take the value from each cell in the excel file, so I canโ€™t take a fixed value.
What VB expression should I use?

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Since it is a GenericValue you can enter a text, numbers, dates, and arrays


Fine lets do one thing
lets check with the value of the CValue, DValue, EValue and FValue
โ€“use a write line activity and mention them like thi

and lets check whether any value is getting displayed in the output panel, share that screenshot as well buddy
if the values are getting displayed we are good enough
or if the values are not getting displayed its clear cut that this issue is because of those null values
โ€“and if there are null values we need to check with the way the excel file is read and stored and need to check what is the source of these variables in your workflow

Kindly try this and let know for any queries or clarification
Cheers @mcLauge