Why is my lamda null when sorting a list?

Asked Jul 10 '20 at 15:26

Active Jul 10 '20 at 15:28

Viewed 25 times

I have a class called Books, I am creating a list and populating it as follows

List<Books> booklist = new List<Books>();

foreach (BooksUsers bu in userbooks)
{
    Books book = _context.Books.Where(b => b.BookId == bu.BookId).Where(b => b.Void == false).FirstOrDefault();
    booklist.Add(book);
}

I want to sort the list by BookTitle, and am getting null reference exceptions on the lambda

I tired this

booklist.Sort((x, y) => x.BookTitle.CompareTo(y.BookTitle));

But get this

Object reference not set to an instance of an object. x was null.

I tried this

List<Books> SortedList = booklist.OrderBy(o => o.BookTitle).ToList();

Object reference not set to an instance of an object. o was null.

and this

booklist.OrderBy(bl => bl.BookTitle).ToList();

Object reference not set to an instance of an object. bl was null.

booklist has items.

Can anyone shed some light?

edited Jul 10 '20 at 15:28

dymanoid

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asked Jul 10 '20 at 15:26

John Bellew

Clearly something that list is null. You will have to debug your code to figure out what it is. – Lasse V. Karlsen Jul 10 '20 at 15:27
One of your books is null. – Haytam Jul 10 '20 at 15:28
Yes, it is, thank you – John Bellew Jul 10 '20 at 15:34
1

if (book != null) { booklist.Add(book); } – John Bellew Jul 10 '20 at 15:34

Why is my lamda null when sorting a list?

0 Answers0