DataTable.Merge returns "Expression does not produce a value" Error

[stevenvd]

Hello

Browsing through the forums I encountered this error a fair few times, but none of the solutions seem to work in case of merging Data.Tables.

Add to Dictionary: the expression does not produce a value

[image] Hi everyone!! I ask you, kindly, a hand for a problem I have encountered but which I can not understand. As you can see from the image, I’m trying to add a value of type String.String to a list value inside a dictionary. But UiPath gives me an error with the following words: The expression does not produce a value. I can not understand why you give me such an exception, neither how to solve this exception. If someone can help me, I kindly ask you to come forward Thanks in advance…

Use of Invoke Method

Below is the code ds.tables(“kitti”).rows.tostring — Output —> System.Data.DataRowCollection and ds.tables(0).tablename.tostring() – Output —> Kitti (unless you are creating anaother DataTable with name TableName before Kitti) [image]

When I try to use the ‘Invoke Method’ activity I get the following error:

“‘DataTable’ does not have a public instance method named ‘Merge’ matching the parameter types, generic type arguments, and generic type constraints supplied to InvokeMethod ‘Invoke Method’.”

This is what it looks like in UiPath

Thanks for your time.

[ClaytonM]

Have you considered using the “Merge Data Table” activity?

[ClaytonM]

Also, I think you are getting that error because your Parameters are wrong. You should have one datatable as an In argument of type DataTable.

[stevenvd]

Thanks for your reply!

I forgot to input the parameters indeed.

The parameters should look like this:

Where the value (ExtractDataTable) is the DataTable that will be added.

And the TargetObject (FinalTable) is the DataTable that will be updated.

I’ll try out the ‘Merge Data Table’ activity as well.