Linq statement return error when no record found

THe linq statement below return an exception error when no match record found. Is there anyway to handle this?, Please advise, thank you

AdventureEntities hem = new AdventureEntities ();
Guid productId;

Adventure.Product list= hem.Product .Where(x => x.Product== productId).FirstOrDefault();

No, that shouldn't throw an exception. It will, however, set list to null - because that's what FirstOrDefault does when there are no results.

If you then dereference list, you'll get a NullReferenceException. You can avoid this by just checking for nullity first:

if (list != null)
{
    // Use the list
}

Also note that you can use the overload of FirstOrDefault which accepts a predicate, to make the code simpler:

var list = hem.Product.FirstOrDefault(x => x.Product== productId);

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