How to check null for all participants in a union LINQ
Sep 15, 2022
As an example for the following scenario, how can I check whether quizType1Attempt and/or quizType2Attempt is null (without checking before these statements)?
var resultRecord = studentDomain.quizType1Attempts.Select(quizType1Attempt => new resultRecord {
Id = quizType1Attempt.Id,
Subject = quizType1Attempt.Subject,
...
}).Union(studentDomain.quizType2Attempts.Select(quizType2Attempt => new resultRecord {
Id = quizType2Attempt.Id,
Subject = quizType2Attempt.Subject
...
})).ToList();
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Answers (1)
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You can add a Where() predicate to filter your items in the list.
var resultRecord = studentDomain.quizType1Attempts.Where(q1 => q1 != null).Select(quizType1Attempt => new resultRecord {
Id = quizType1Attempt.Id,
Subject = quizType1Attempt.Subject,
...
}).Union(studentDomain.quizType2Attempts.Where(q2 => q2 != null).Select(quizType2Attempt => new resultRecord {
Id = quizType2Attempt.Id,
Subject = quizType2Attempt.Subject
...
})).ToList();
