Question

Any ideas why LINQ to Entities doesn’t support SingleOrDefault() but instead ask to use FirstOrDefault()?

Will SingleOrDefault() functionality be replaced? By what?

Answer 1

I’m not sure why it was left out, but you can always roll your own.

I found a similar response to this question on MSDN, here is an implementation based off of that code.

public static TElement SingleOrDefault<TElement>
      (this IQueryable<TElement> query)
{
    if (query.Count() == 1)
        return query.First();
    else if (query.Count() == 0)
        return null;
    else
        throw new InvalidOperationException();
}


// Use it like this

Product prod = (from p in db.Product
                where p.ProductID == 711
                select p).SingleOrDefault();

Source: MSDN