Save distinct values in a column conditionally to a list

Asked Dec 16 '19 at 20:42

Active Jan 17 '20 at 10:12

Viewed 101 times

I have the following which has worked for me so far, however I now want to only select locations if another column (Location ID) is not null. How do I add this filter to my list?

Location and Location ID are both columns in datatable dt.

EDIT: edited code to try to match what was in the comments. I also tried != "" and the list isn't populated either way.

Last edit: The below code didn't work because I had dt as var originally. Removing the var and just declaring the datatable fixed it and it now works correctly.

var distinctLocs = dt.AsEnumerable()
               .Where(s => s.Field<string>("Location ID") != null)
               .Select(s => new
               {
                   id = s.Field<string>("Location"),
               })
               .Distinct().ToList();

edited Jan 17 '20 at 10:12

Nguyễn Văn Phong

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asked Dec 16 '19 at 20:42

Mikael

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`dt.AsEnumerable().Where(s => s.Location_ID != null).Select(...).....` – dcg Dec 16 '19 at 20:43
Is Location_ID a foreign key, and is Location a string field or an associated table? – jasonmchoe Dec 16 '19 at 21:00
There's nothing obviously wrong with your code. But then, we have no [mcve] to check. – Gert Arnold Dec 16 '19 at 21:29
You've tried running this, I assume? What happens? – robbpriestley Dec 17 '19 at 02:35
Does this answer your question? [What is the difference between null and System.DBNull.Value?](https://stackoverflow.com/questions/4958379/what-is-the-difference-between-null-and-system-dbnull-value) – Nguyễn Văn Phong Jan 17 '20 at 12:20

Save distinct values in a column conditionally to a list

0 Answers0