Linq ?? operator means

Question

Good Day.

Sorry before i'm a beginner on linq. can i ask what is the meaning of ?? in linq

.Where(w => ((w.BalancedDate ?? w.OriginalDateByAMT) >= filter.start_date && (w.BalancedDate ?? w.OriginalDateByAMT) <= filter.end_date) || w.ReplaceByEHValidation == true)

Thanks

@Aomine so it means that if w.BalancedDate is null then it will be replaced by w.OriginalDateByAMT value? — Jackie, Dec 18 '18 at 03:24
Correct, if `w.BalancedDate` is null then `w.OriginalDateByAMT` will be used for the comparison. — Ousmane D., Dec 18 '18 at 03:25

score 2 · Accepted Answer · answered Dec 18 '18 at 03:24

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It's not a linq operator, but it means if the left hand property is null, then use the right hand property.

answered Dec 18 '18 at 03:24

Keith Rousseau

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So its like COALESCE or ISNULL on SQL? – Jackie Dec 18 '18 at 03:25
@Randy, Exactly, in fact it's call the null coalescing operator https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-coalescing-operator – juharr Dec 18 '18 at 03:56

score 1 · Answer 2 · answered Dec 18 '18 at 03:27

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If the value on the left side of ?? is null, then it takes the value of the right side.

I.e.

var x = y ?? z;

If y is not null then x=y otherwise x=z

answered Dec 18 '18 at 03:27

Ro.

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score 0 · Answer 3 · answered Dec 18 '18 at 03:25

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Yes, this question was already answered on the link shared on the comments. It is a Nullable type or null-coalescing, it returns the left value if not null or else it returns the right one.

answered Dec 18 '18 at 03:25

John Mor

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Linq ?? operator means

3 Answers3