Error in linq query

Learning Hub Academy Feedback
, , ,
1

Hi all,

we have read range activity with varDataTable = dtInput and assing with linq query.
In attached the file input
File input.xlsx (8.9 KB)

Below the query used

dtFinal1 = dtInput.AsEnumerable().Where(Function(row) Not dtFinal1.AsEnumerable().
Select(Function(r) r.Field(Of String)(“Concat”)).Any(Function(x) x = row.Field(Of String)(“Concat”))).
CopyToDataTable()

when we execute this workflow we have this issue

image
image580×266 7.09 KB

In attached the workflow:
test.zip (2.7 KB)

Could you support us?

Thanks in advanced
S.

2

@salvatore.quimi

May I know what you trying to do with Linq query here. If possible can you please share some sample input and output data.

3

The error message is self explanatory. You have a null value. Have you run it in Debug so when the error occurs you can look at the values?

4

hi @postwick,

I have shared the workflow to verify by yourself. Anycase I have runned in debug but the values is not empty.

Could you support?

Thanks

5

I’m talking about the value returned by the LINQ query. If it returns no rows…

6

Hi,

Your expression in the project contains dtFinal in right side as the following. It causes the exception.

img20220422-1
img20220422-1798×457 13.4 KB

Regards,

7

Hi @Yoichi

what do you mean “Your expression in the project contains dtFinal in right side” ?
I see the same value dtFinal1 in left side and in right side:

image
image1015×660 16.4 KB

Could you support?

Thanks

8

Hello @salvatore.quimi ,

Please change the linq like this:
dtInput.AsEnumerable().Where(Function(row) Not dtInput.AsEnumerable().
Select(Function(r) r.Field(Of String)(“Concat”)).Any(Function(x) x = row.Field(Of String)(“Concat”))).
CopyToDataTable()

As @Yoichi explained, you had DtFinal in the right side which caused the exception.
Thanks!
Athira

9

dtFinal1 is null because it was never initialized. So when UiPath is trying to execute dtFinal1.AsEnumerable() in the LINQ statement, it is executing null.AsEnumerable(), which simply doesn’t work.

Test to initialize dtFinal1 with e.g. dtInput.Clone (it will copy the data table structure but not the rows).

image

10

Hi @athira.somasekharan

thanks for your suggestion, I have changed the linq like you suggested, but now I have this issue:

image
image1465×750 181 KB

“Assing: The source contains no DataRows” → but as my screen dtInput contains data

Could you support?

Thanks in advanced!!!

11

Hello @salvatore.quimi ,

Then @ptrobot 's solution makes more sense. Please try it out!
Also, can you plean explain what you are trying to achieve here?

Thanks!
Athira

12

Hi @athira.somasekharan and @ptrobot

I also tried dtFinal1 = dtInput.copy and dtInput.clone as below:

image
image1458×935 79.6 KB

but I always have the same error,
I used this expression in a process that has been working for months, but since yesterday I have this problem

Any suggestion?

13

Did you revert the change after testing @athira.somasekharan solution?

Just tested on my computer and it’s working without error:

image
image1583×642 40 KB

14

Hi @ptrobot

now it works, thanks a lot!!!

Best Regards